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kernel/futex.c
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/* * Fast Userspace Mutexes (which I call "Futexes!"). * (C) Rusty Russell, IBM 2002 * * Generalized futexes, futex requeueing, misc fixes by Ingo Molnar * (C) Copyright 2003 Red Hat Inc, All Rights Reserved * * Removed page pinning, fix privately mapped COW pages and other cleanups * (C) Copyright 2003, 2004 Jamie Lokier * |
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* Robust futex support started by Ingo Molnar * (C) Copyright 2006 Red Hat Inc, All Rights Reserved * Thanks to Thomas Gleixner for suggestions, analysis and fixes. * |
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* PI-futex support started by Ingo Molnar and Thomas Gleixner * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> * Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com> * |
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* PRIVATE futexes by Eric Dumazet * Copyright (C) 2007 Eric Dumazet <dada1@cosmosbay.com> * |
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* Requeue-PI support by Darren Hart <dvhltc@us.ibm.com> * Copyright (C) IBM Corporation, 2009 * Thanks to Thomas Gleixner for conceptual design and careful reviews. * |
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* Thanks to Ben LaHaise for yelling "hashed waitqueues" loudly * enough at me, Linus for the original (flawed) idea, Matthew * Kirkwood for proof-of-concept implementation. * * "The futexes are also cursed." * "But they come in a choice of three flavours!" * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/slab.h> #include <linux/poll.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/jhash.h> #include <linux/init.h> #include <linux/futex.h> #include <linux/mount.h> #include <linux/pagemap.h> #include <linux/syscalls.h> |
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#include <linux/signal.h> |
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#include <linux/export.h> |
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#include <linux/magic.h> |
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#include <linux/pid.h> #include <linux/nsproxy.h> |
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#include <linux/ptrace.h> |
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#include <linux/sched/rt.h> |
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#include <linux/hugetlb.h> |
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#include <linux/freezer.h> |
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#include <linux/bootmem.h> |
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#include <asm/futex.h> |
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#include "locking/rtmutex_common.h" |
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/* |
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* READ this before attempting to hack on futexes! * * Basic futex operation and ordering guarantees * ============================================= |
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* * The waiter reads the futex value in user space and calls * futex_wait(). This function computes the hash bucket and acquires * the hash bucket lock. After that it reads the futex user space value |
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* again and verifies that the data has not changed. If it has not changed * it enqueues itself into the hash bucket, releases the hash bucket lock * and schedules. |
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* * The waker side modifies the user space value of the futex and calls |
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* futex_wake(). This function computes the hash bucket and acquires the * hash bucket lock. Then it looks for waiters on that futex in the hash * bucket and wakes them. |
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* |
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* In futex wake up scenarios where no tasks are blocked on a futex, taking * the hb spinlock can be avoided and simply return. In order for this * optimization to work, ordering guarantees must exist so that the waiter * being added to the list is acknowledged when the list is concurrently being * checked by the waker, avoiding scenarios like the following: |
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* * CPU 0 CPU 1 * val = *futex; * sys_futex(WAIT, futex, val); * futex_wait(futex, val); * uval = *futex; * *futex = newval; * sys_futex(WAKE, futex); * futex_wake(futex); * if (queue_empty()) * return; * if (uval == val) * lock(hash_bucket(futex)); * queue(); * unlock(hash_bucket(futex)); * schedule(); * * This would cause the waiter on CPU 0 to wait forever because it * missed the transition of the user space value from val to newval * and the waker did not find the waiter in the hash bucket queue. |
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* |
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* The correct serialization ensures that a waiter either observes * the changed user space value before blocking or is woken by a * concurrent waker: * * CPU 0 CPU 1 |
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* val = *futex; * sys_futex(WAIT, futex, val); * futex_wait(futex, val); |
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* |
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* waiters++; (a) |
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* mb(); (A) <-- paired with -. * | * lock(hash_bucket(futex)); | * | * uval = *futex; | * | *futex = newval; * | sys_futex(WAKE, futex); * | futex_wake(futex); * | * `-------> mb(); (B) |
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* if (uval == val) |
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* queue(); |
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* unlock(hash_bucket(futex)); |
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* schedule(); if (waiters) * lock(hash_bucket(futex)); |
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* else wake_waiters(futex); * waiters--; (b) unlock(hash_bucket(futex)); |
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* |
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* Where (A) orders the waiters increment and the futex value read through * atomic operations (see hb_waiters_inc) and where (B) orders the write * to futex and the waiters read -- this is done by the barriers in * get_futex_key_refs(), through either ihold or atomic_inc, depending on the * futex type. |
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* * This yields the following case (where X:=waiters, Y:=futex): * * X = Y = 0 * * w[X]=1 w[Y]=1 * MB MB * r[Y]=y r[X]=x * * Which guarantees that x==0 && y==0 is impossible; which translates back into * the guarantee that we cannot both miss the futex variable change and the * enqueue. |
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* * Note that a new waiter is accounted for in (a) even when it is possible that * the wait call can return error, in which case we backtrack from it in (b). * Refer to the comment in queue_lock(). * * Similarly, in order to account for waiters being requeued on another * address we always increment the waiters for the destination bucket before * acquiring the lock. It then decrements them again after releasing it - * the code that actually moves the futex(es) between hash buckets (requeue_futex) * will do the additional required waiter count housekeeping. This is done for * double_lock_hb() and double_unlock_hb(), respectively. |
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*/ |
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#ifndef CONFIG_HAVE_FUTEX_CMPXCHG |
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int __read_mostly futex_cmpxchg_enabled; |
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#endif |
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/* |
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* Futex flags used to encode options to functions and preserve them across * restarts. */ #define FLAGS_SHARED 0x01 #define FLAGS_CLOCKRT 0x02 #define FLAGS_HAS_TIMEOUT 0x04 /* |
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* Priority Inheritance state: */ struct futex_pi_state { /* * list of 'owned' pi_state instances - these have to be * cleaned up in do_exit() if the task exits prematurely: */ struct list_head list; /* * The PI object: */ struct rt_mutex pi_mutex; struct task_struct *owner; atomic_t refcount; union futex_key key; }; |
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/** * struct futex_q - The hashed futex queue entry, one per waiting task |
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* @list: priority-sorted list of tasks waiting on this futex |
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* @task: the task waiting on the futex * @lock_ptr: the hash bucket lock * @key: the key the futex is hashed on * @pi_state: optional priority inheritance state * @rt_waiter: rt_waiter storage for use with requeue_pi * @requeue_pi_key: the requeue_pi target futex key * @bitset: bitset for the optional bitmasked wakeup * * We use this hashed waitqueue, instead of a normal wait_queue_t, so |
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* we can wake only the relevant ones (hashed queues may be shared). * * A futex_q has a woken state, just like tasks have TASK_RUNNING. |
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* It is considered woken when plist_node_empty(&q->list) || q->lock_ptr == 0. |
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* The order of wakeup is always to make the first condition true, then |
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* the second. * * PI futexes are typically woken before they are removed from the hash list via * the rt_mutex code. See unqueue_me_pi(). |
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*/ struct futex_q { |
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struct plist_node list; |
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|
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struct task_struct *task; |
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spinlock_t *lock_ptr; |
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union futex_key key; |
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struct futex_pi_state *pi_state; |
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struct rt_mutex_waiter *rt_waiter; |
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union futex_key *requeue_pi_key; |
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u32 bitset; |
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}; |
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static const struct futex_q futex_q_init = { /* list gets initialized in queue_me()*/ .key = FUTEX_KEY_INIT, .bitset = FUTEX_BITSET_MATCH_ANY }; |
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/* |
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* Hash buckets are shared by all the futex_keys that hash to the same * location. Each key may have multiple futex_q structures, one for each task * waiting on a futex. |
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*/ struct futex_hash_bucket { |
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atomic_t waiters; |
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spinlock_t lock; struct plist_head chain; |
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} ____cacheline_aligned_in_smp; |
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static unsigned long __read_mostly futex_hashsize; static struct futex_hash_bucket *futex_queues; |
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static inline void futex_get_mm(union futex_key *key) { atomic_inc(&key->private.mm->mm_count); /* * Ensure futex_get_mm() implies a full barrier such that * get_futex_key() implies a full barrier. This is relied upon * as full barrier (B), see the ordering comment above. */ smp_mb__after_atomic_inc(); } |
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/* * Reflects a new waiter being added to the waitqueue. */ static inline void hb_waiters_inc(struct futex_hash_bucket *hb) |
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{ #ifdef CONFIG_SMP |
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atomic_inc(&hb->waiters); |
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/* |
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* Full barrier (A), see the ordering comment above. |
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*/ |
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smp_mb__after_atomic_inc(); #endif } /* * Reflects a waiter being removed from the waitqueue by wakeup * paths. */ static inline void hb_waiters_dec(struct futex_hash_bucket *hb) { #ifdef CONFIG_SMP atomic_dec(&hb->waiters); #endif } |
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static inline int hb_waiters_pending(struct futex_hash_bucket *hb) { #ifdef CONFIG_SMP return atomic_read(&hb->waiters); |
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#else |
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return 1; |
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#endif } |
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/* * We hash on the keys returned from get_futex_key (see below). */ static struct futex_hash_bucket *hash_futex(union futex_key *key) { u32 hash = jhash2((u32*)&key->both.word, (sizeof(key->both.word)+sizeof(key->both.ptr))/4, key->both.offset); |
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return &futex_queues[hash & (futex_hashsize - 1)]; |
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} /* * Return 1 if two futex_keys are equal, 0 otherwise. */ static inline int match_futex(union futex_key *key1, union futex_key *key2) { |
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return (key1 && key2 && key1->both.word == key2->both.word |
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&& key1->both.ptr == key2->both.ptr && key1->both.offset == key2->both.offset); } |
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/* * Take a reference to the resource addressed by a key. * Can be called while holding spinlocks. * */ static void get_futex_key_refs(union futex_key *key) { if (!key->both.ptr) return; switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) { case FUT_OFF_INODE: |
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ihold(key->shared.inode); /* implies MB (B) */ |
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break; case FUT_OFF_MMSHARED: |
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futex_get_mm(key); /* implies MB (B) */ |
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break; } } /* * Drop a reference to the resource addressed by a key. * The hash bucket spinlock must not be held. */ static void drop_futex_key_refs(union futex_key *key) { |
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if (!key->both.ptr) { /* If we're here then we tried to put a key we failed to get */ WARN_ON_ONCE(1); |
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return; |
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} |
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switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) { case FUT_OFF_INODE: iput(key->shared.inode); break; case FUT_OFF_MMSHARED: mmdrop(key->private.mm); break; } } |
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/** |
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* get_futex_key() - Get parameters which are the keys for a futex * @uaddr: virtual address of the futex * @fshared: 0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED * @key: address where result is stored. |
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* @rw: mapping needs to be read/write (values: VERIFY_READ, * VERIFY_WRITE) |
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* |
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* Return: a negative error code or 0 * |
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* The key words are stored in *key on success. |
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* |
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* For shared mappings, it's (page->index, file_inode(vma->vm_file), |
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* offset_within_page). For private mappings, it's (uaddr, current->mm). * We can usually work out the index without swapping in the page. * |
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* lock_page() might sleep, the caller should not hold a spinlock. |
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*/ |
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static int |
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get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw) |
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{ |
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unsigned long address = (unsigned long)uaddr; |
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struct mm_struct *mm = current->mm; |
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struct page *page, *page_head; |
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int err, ro = 0; |
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/* * The futex address must be "naturally" aligned. */ |
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key->both.offset = address % PAGE_SIZE; |
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if (unlikely((address % sizeof(u32)) != 0)) |
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return -EINVAL; |
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address -= key->both.offset; |
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|
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if (unlikely(!access_ok(rw, uaddr, sizeof(u32)))) return -EFAULT; |
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/* |
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* PROCESS_PRIVATE futexes are fast. * As the mm cannot disappear under us and the 'key' only needs * virtual address, we dont even have to find the underlying vma. * Note : We do have to check 'uaddr' is a valid user address, * but access_ok() should be faster than find_vma() */ if (!fshared) { |
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key->private.mm = mm; key->private.address = address; |
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get_futex_key_refs(key); /* implies MB (B) */ |
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return 0; } |
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again: |
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err = get_user_pages_fast(address, 1, 1, &page); |
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/* * If write access is not required (eg. FUTEX_WAIT), try * and get read-only access. */ if (err == -EFAULT && rw == VERIFY_READ) { err = get_user_pages_fast(address, 1, 0, &page); ro = 1; } |
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if (err < 0) return err; |
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else err = 0; |
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE page_head = page; if (unlikely(PageTail(page))) { |
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put_page(page); |
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/* serialize against __split_huge_page_splitting() */ local_irq_disable(); |
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if (likely(__get_user_pages_fast(address, 1, !ro, &page) == 1)) { |
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page_head = compound_head(page); /* * page_head is valid pointer but we must pin * it before taking the PG_lock and/or * PG_compound_lock. The moment we re-enable * irqs __split_huge_page_splitting() can * return and the head page can be freed from * under us. We can't take the PG_lock and/or * PG_compound_lock on a page that could be * freed from under us. */ if (page != page_head) { get_page(page_head); put_page(page); } local_irq_enable(); } else { local_irq_enable(); goto again; } } #else page_head = compound_head(page); if (page != page_head) { get_page(page_head); put_page(page); } #endif lock_page(page_head); |
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/* * If page_head->mapping is NULL, then it cannot be a PageAnon * page; but it might be the ZERO_PAGE or in the gate area or * in a special mapping (all cases which we are happy to fail); * or it may have been a good file page when get_user_pages_fast * found it, but truncated or holepunched or subjected to * invalidate_complete_page2 before we got the page lock (also * cases which we are happy to fail). And we hold a reference, * so refcount care in invalidate_complete_page's remove_mapping * prevents drop_caches from setting mapping to NULL beneath us. * * The case we do have to guard against is when memory pressure made * shmem_writepage move it from filecache to swapcache beneath us: * an unlikely race, but we do need to retry for page_head->mapping. */ |
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if (!page_head->mapping) { |
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482 |
int shmem_swizzled = PageSwapCache(page_head); |
a5b338f2b thp: update futex... |
483 484 |
unlock_page(page_head); put_page(page_head); |
e6780f724 futex: Fix uninte... |
485 486 487 |
if (shmem_swizzled) goto again; return -EFAULT; |
38d47c1b7 futex: rely on ge... |
488 |
} |
1da177e4c Linux-2.6.12-rc2 |
489 490 491 492 493 494 |
/* * Private mappings are handled in a simple way. * * NOTE: When userspace waits on a MAP_SHARED mapping, even if * it's a read-only handle, it's expected that futexes attach to |
38d47c1b7 futex: rely on ge... |
495 |
* the object not the particular process. |
1da177e4c Linux-2.6.12-rc2 |
496 |
*/ |
a5b338f2b thp: update futex... |
497 |
if (PageAnon(page_head)) { |
9ea71503a futex: Fix regres... |
498 499 500 501 502 503 504 505 |
/* * A RO anonymous page will never change and thus doesn't make * sense for futex operations. */ if (ro) { err = -EFAULT; goto out; } |
38d47c1b7 futex: rely on ge... |
506 |
key->both.offset |= FUT_OFF_MMSHARED; /* ref taken on mm */ |
1da177e4c Linux-2.6.12-rc2 |
507 |
key->private.mm = mm; |
e2970f2fb [PATCH] pi-futex:... |
508 |
key->private.address = address; |
38d47c1b7 futex: rely on ge... |
509 510 |
} else { key->both.offset |= FUT_OFF_INODE; /* inode-based key */ |
a5b338f2b thp: update futex... |
511 |
key->shared.inode = page_head->mapping->host; |
13d60f4b6 futex: Take hugep... |
512 |
key->shared.pgoff = basepage_index(page); |
1da177e4c Linux-2.6.12-rc2 |
513 |
} |
b0c29f79e futexes: Avoid ta... |
514 |
get_futex_key_refs(key); /* implies MB (B) */ |
1da177e4c Linux-2.6.12-rc2 |
515 |
|
9ea71503a futex: Fix regres... |
516 |
out: |
a5b338f2b thp: update futex... |
517 518 |
unlock_page(page_head); put_page(page_head); |
9ea71503a futex: Fix regres... |
519 |
return err; |
1da177e4c Linux-2.6.12-rc2 |
520 |
} |
ae791a2d2 futex: Cleanup st... |
521 |
static inline void put_futex_key(union futex_key *key) |
1da177e4c Linux-2.6.12-rc2 |
522 |
{ |
38d47c1b7 futex: rely on ge... |
523 |
drop_futex_key_refs(key); |
1da177e4c Linux-2.6.12-rc2 |
524 |
} |
d96ee56ce futex: Make funct... |
525 526 |
/** * fault_in_user_writeable() - Fault in user address and verify RW access |
d0725992c futex: Fix the wr... |
527 528 529 530 531 |
* @uaddr: pointer to faulting user space address * * Slow path to fixup the fault we just took in the atomic write * access to @uaddr. * |
fb62db2ba futex: Fix kernel... |
532 |
* We have no generic implementation of a non-destructive write to the |
d0725992c futex: Fix the wr... |
533 534 535 536 537 538 |
* user address. We know that we faulted in the atomic pagefault * disabled section so we can as well avoid the #PF overhead by * calling get_user_pages() right away. */ static int fault_in_user_writeable(u32 __user *uaddr) { |
722d01723 futex: Take mmap_... |
539 540 541 542 |
struct mm_struct *mm = current->mm; int ret; down_read(&mm->mmap_sem); |
2efaca927 mm/futex: fix fut... |
543 544 |
ret = fixup_user_fault(current, mm, (unsigned long)uaddr, FAULT_FLAG_WRITE); |
722d01723 futex: Take mmap_... |
545 |
up_read(&mm->mmap_sem); |
d0725992c futex: Fix the wr... |
546 547 |
return ret < 0 ? ret : 0; } |
4b1c486b3 futex: add helper... |
548 549 |
/** * futex_top_waiter() - Return the highest priority waiter on a futex |
d96ee56ce futex: Make funct... |
550 551 |
* @hb: the hash bucket the futex_q's reside in * @key: the futex key (to distinguish it from other futex futex_q's) |
4b1c486b3 futex: add helper... |
552 553 554 555 556 557 558 559 560 561 562 563 564 565 |
* * Must be called with the hb lock held. */ static struct futex_q *futex_top_waiter(struct futex_hash_bucket *hb, union futex_key *key) { struct futex_q *this; plist_for_each_entry(this, &hb->chain, list) { if (match_futex(&this->key, key)) return this; } return NULL; } |
37a9d912b futex: Sanitize c... |
566 567 |
static int cmpxchg_futex_value_locked(u32 *curval, u32 __user *uaddr, u32 uval, u32 newval) |
36cf3b5c3 FUTEX: Tidy up th... |
568 |
{ |
37a9d912b futex: Sanitize c... |
569 |
int ret; |
36cf3b5c3 FUTEX: Tidy up th... |
570 571 |
pagefault_disable(); |
37a9d912b futex: Sanitize c... |
572 |
ret = futex_atomic_cmpxchg_inatomic(curval, uaddr, uval, newval); |
36cf3b5c3 FUTEX: Tidy up th... |
573 |
pagefault_enable(); |
37a9d912b futex: Sanitize c... |
574 |
return ret; |
36cf3b5c3 FUTEX: Tidy up th... |
575 576 577 |
} static int get_futex_value_locked(u32 *dest, u32 __user *from) |
1da177e4c Linux-2.6.12-rc2 |
578 579 |
{ int ret; |
a866374ae [PATCH] mm: pagef... |
580 |
pagefault_disable(); |
e2970f2fb [PATCH] pi-futex:... |
581 |
ret = __copy_from_user_inatomic(dest, from, sizeof(u32)); |
a866374ae [PATCH] mm: pagef... |
582 |
pagefault_enable(); |
1da177e4c Linux-2.6.12-rc2 |
583 584 585 |
return ret ? -EFAULT : 0; } |
c87e2837b [PATCH] pi-futex:... |
586 587 588 589 590 591 592 593 594 595 |
/* * PI code: */ static int refill_pi_state_cache(void) { struct futex_pi_state *pi_state; if (likely(current->pi_state_cache)) return 0; |
4668edc33 [PATCH] kernel co... |
596 |
pi_state = kzalloc(sizeof(*pi_state), GFP_KERNEL); |
c87e2837b [PATCH] pi-futex:... |
597 598 599 |
if (!pi_state) return -ENOMEM; |
c87e2837b [PATCH] pi-futex:... |
600 601 602 603 |
INIT_LIST_HEAD(&pi_state->list); /* pi_mutex gets initialized later */ pi_state->owner = NULL; atomic_set(&pi_state->refcount, 1); |
38d47c1b7 futex: rely on ge... |
604 |
pi_state->key = FUTEX_KEY_INIT; |
c87e2837b [PATCH] pi-futex:... |
605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 |
current->pi_state_cache = pi_state; return 0; } static struct futex_pi_state * alloc_pi_state(void) { struct futex_pi_state *pi_state = current->pi_state_cache; WARN_ON(!pi_state); current->pi_state_cache = NULL; return pi_state; } static void free_pi_state(struct futex_pi_state *pi_state) { if (!atomic_dec_and_test(&pi_state->refcount)) return; /* * If pi_state->owner is NULL, the owner is most probably dying * and has cleaned up the pi_state already */ if (pi_state->owner) { |
1d6154825 sched: Convert pi... |
631 |
raw_spin_lock_irq(&pi_state->owner->pi_lock); |
c87e2837b [PATCH] pi-futex:... |
632 |
list_del_init(&pi_state->list); |
1d6154825 sched: Convert pi... |
633 |
raw_spin_unlock_irq(&pi_state->owner->pi_lock); |
c87e2837b [PATCH] pi-futex:... |
634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 |
rt_mutex_proxy_unlock(&pi_state->pi_mutex, pi_state->owner); } if (current->pi_state_cache) kfree(pi_state); else { /* * pi_state->list is already empty. * clear pi_state->owner. * refcount is at 0 - put it back to 1. */ pi_state->owner = NULL; atomic_set(&pi_state->refcount, 1); current->pi_state_cache = pi_state; } } /* * Look up the task based on what TID userspace gave us. * We dont trust it. */ static struct task_struct * futex_find_get_task(pid_t pid) { struct task_struct *p; |
d359b549b [PATCH] futex_fin... |
659 |
rcu_read_lock(); |
228ebcbe6 Uninline find_tas... |
660 |
p = find_task_by_vpid(pid); |
7a0ea09ad futex: futex_find... |
661 662 |
if (p) get_task_struct(p); |
a06381fec FUTEX: Restore th... |
663 |
|
d359b549b [PATCH] futex_fin... |
664 |
rcu_read_unlock(); |
c87e2837b [PATCH] pi-futex:... |
665 666 667 668 669 670 671 672 673 674 675 |
return p; } /* * This task is holding PI mutexes at exit time => bad. * Kernel cleans up PI-state, but userspace is likely hosed. * (Robust-futex cleanup is separate and might save the day for userspace.) */ void exit_pi_state_list(struct task_struct *curr) { |
c87e2837b [PATCH] pi-futex:... |
676 677 |
struct list_head *next, *head = &curr->pi_state_list; struct futex_pi_state *pi_state; |
627371d73 [PATCH] pi-futex:... |
678 |
struct futex_hash_bucket *hb; |
38d47c1b7 futex: rely on ge... |
679 |
union futex_key key = FUTEX_KEY_INIT; |
c87e2837b [PATCH] pi-futex:... |
680 |
|
a0c1e9073 futex: runtime en... |
681 682 |
if (!futex_cmpxchg_enabled) return; |
c87e2837b [PATCH] pi-futex:... |
683 684 685 |
/* * We are a ZOMBIE and nobody can enqueue itself on * pi_state_list anymore, but we have to be careful |
627371d73 [PATCH] pi-futex:... |
686 |
* versus waiters unqueueing themselves: |
c87e2837b [PATCH] pi-futex:... |
687 |
*/ |
1d6154825 sched: Convert pi... |
688 |
raw_spin_lock_irq(&curr->pi_lock); |
c87e2837b [PATCH] pi-futex:... |
689 690 691 692 693 |
while (!list_empty(head)) { next = head->next; pi_state = list_entry(next, struct futex_pi_state, list); key = pi_state->key; |
627371d73 [PATCH] pi-futex:... |
694 |
hb = hash_futex(&key); |
1d6154825 sched: Convert pi... |
695 |
raw_spin_unlock_irq(&curr->pi_lock); |
c87e2837b [PATCH] pi-futex:... |
696 |
|
c87e2837b [PATCH] pi-futex:... |
697 |
spin_lock(&hb->lock); |
1d6154825 sched: Convert pi... |
698 |
raw_spin_lock_irq(&curr->pi_lock); |
627371d73 [PATCH] pi-futex:... |
699 700 701 702 |
/* * We dropped the pi-lock, so re-check whether this * task still owns the PI-state: */ |
c87e2837b [PATCH] pi-futex:... |
703 704 705 706 |
if (head->next != next) { spin_unlock(&hb->lock); continue; } |
c87e2837b [PATCH] pi-futex:... |
707 |
WARN_ON(pi_state->owner != curr); |
627371d73 [PATCH] pi-futex:... |
708 709 |
WARN_ON(list_empty(&pi_state->list)); list_del_init(&pi_state->list); |
c87e2837b [PATCH] pi-futex:... |
710 |
pi_state->owner = NULL; |
1d6154825 sched: Convert pi... |
711 |
raw_spin_unlock_irq(&curr->pi_lock); |
c87e2837b [PATCH] pi-futex:... |
712 713 714 715 |
rt_mutex_unlock(&pi_state->pi_mutex); spin_unlock(&hb->lock); |
1d6154825 sched: Convert pi... |
716 |
raw_spin_lock_irq(&curr->pi_lock); |
c87e2837b [PATCH] pi-futex:... |
717 |
} |
1d6154825 sched: Convert pi... |
718 |
raw_spin_unlock_irq(&curr->pi_lock); |
c87e2837b [PATCH] pi-futex:... |
719 720 721 |
} static int |
d0aa7a70b futex_requeue_pi ... |
722 723 |
lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, union futex_key *key, struct futex_pi_state **ps) |
c87e2837b [PATCH] pi-futex:... |
724 725 726 |
{ struct futex_pi_state *pi_state = NULL; struct futex_q *this, *next; |
c87e2837b [PATCH] pi-futex:... |
727 |
struct task_struct *p; |
778e9a9c3 pi-futex: fix exi... |
728 |
pid_t pid = uval & FUTEX_TID_MASK; |
c87e2837b [PATCH] pi-futex:... |
729 |
|
0d00c7b20 futexes: Clean up... |
730 |
plist_for_each_entry_safe(this, next, &hb->chain, list) { |
d0aa7a70b futex_requeue_pi ... |
731 |
if (match_futex(&this->key, key)) { |
c87e2837b [PATCH] pi-futex:... |
732 733 734 735 736 |
/* * Another waiter already exists - bump up * the refcount and return its pi_state: */ pi_state = this->pi_state; |
06a9ec291 [PATCH] pi-futex:... |
737 |
/* |
fb62db2ba futex: Fix kernel... |
738 |
* Userspace might have messed up non-PI and PI futexes |
06a9ec291 [PATCH] pi-futex:... |
739 740 741 |
*/ if (unlikely(!pi_state)) return -EINVAL; |
627371d73 [PATCH] pi-futex:... |
742 |
WARN_ON(!atomic_read(&pi_state->refcount)); |
59647b6ac futex: Handle fut... |
743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 |
/* * When pi_state->owner is NULL then the owner died * and another waiter is on the fly. pi_state->owner * is fixed up by the task which acquires * pi_state->rt_mutex. * * We do not check for pid == 0 which can happen when * the owner died and robust_list_exit() cleared the * TID. */ if (pid && pi_state->owner) { /* * Bail out if user space manipulated the * futex value. */ if (pid != task_pid_vnr(pi_state->owner)) return -EINVAL; } |
627371d73 [PATCH] pi-futex:... |
762 |
|
c87e2837b [PATCH] pi-futex:... |
763 |
atomic_inc(&pi_state->refcount); |
d0aa7a70b futex_requeue_pi ... |
764 |
*ps = pi_state; |
c87e2837b [PATCH] pi-futex:... |
765 766 767 768 769 770 |
return 0; } } /* |
e3f2ddeac [PATCH] pi-futex:... |
771 |
* We are the first waiter - try to look up the real owner and attach |
778e9a9c3 pi-futex: fix exi... |
772 |
* the new pi_state to it, but bail out when TID = 0 |
c87e2837b [PATCH] pi-futex:... |
773 |
*/ |
778e9a9c3 pi-futex: fix exi... |
774 |
if (!pid) |
e3f2ddeac [PATCH] pi-futex:... |
775 |
return -ESRCH; |
c87e2837b [PATCH] pi-futex:... |
776 |
p = futex_find_get_task(pid); |
7a0ea09ad futex: futex_find... |
777 778 |
if (!p) return -ESRCH; |
778e9a9c3 pi-futex: fix exi... |
779 780 781 782 783 784 785 |
/* * We need to look at the task state flags to figure out, * whether the task is exiting. To protect against the do_exit * change of the task flags, we do this protected by * p->pi_lock: */ |
1d6154825 sched: Convert pi... |
786 |
raw_spin_lock_irq(&p->pi_lock); |
778e9a9c3 pi-futex: fix exi... |
787 788 789 790 791 792 793 |
if (unlikely(p->flags & PF_EXITING)) { /* * The task is on the way out. When PF_EXITPIDONE is * set, we know that the task has finished the * cleanup: */ int ret = (p->flags & PF_EXITPIDONE) ? -ESRCH : -EAGAIN; |
1d6154825 sched: Convert pi... |
794 |
raw_spin_unlock_irq(&p->pi_lock); |
778e9a9c3 pi-futex: fix exi... |
795 796 797 |
put_task_struct(p); return ret; } |
c87e2837b [PATCH] pi-futex:... |
798 799 800 801 802 803 804 805 806 807 |
pi_state = alloc_pi_state(); /* * Initialize the pi_mutex in locked state and make 'p' * the owner of it: */ rt_mutex_init_proxy_locked(&pi_state->pi_mutex, p); /* Store the key for possible exit cleanups: */ |
d0aa7a70b futex_requeue_pi ... |
808 |
pi_state->key = *key; |
c87e2837b [PATCH] pi-futex:... |
809 |
|
627371d73 [PATCH] pi-futex:... |
810 |
WARN_ON(!list_empty(&pi_state->list)); |
c87e2837b [PATCH] pi-futex:... |
811 812 |
list_add(&pi_state->list, &p->pi_state_list); pi_state->owner = p; |
1d6154825 sched: Convert pi... |
813 |
raw_spin_unlock_irq(&p->pi_lock); |
c87e2837b [PATCH] pi-futex:... |
814 815 |
put_task_struct(p); |
d0aa7a70b futex_requeue_pi ... |
816 |
*ps = pi_state; |
c87e2837b [PATCH] pi-futex:... |
817 818 819 |
return 0; } |
1a52084d0 futex: split out ... |
820 |
/** |
d96ee56ce futex: Make funct... |
821 |
* futex_lock_pi_atomic() - Atomic work required to acquire a pi aware futex |
bab5bc9e8 futex: fixup unlo... |
822 823 824 825 826 827 828 829 |
* @uaddr: the pi futex user address * @hb: the pi futex hash bucket * @key: the futex key associated with uaddr and hb * @ps: the pi_state pointer where we store the result of the * lookup * @task: the task to perform the atomic lock work for. This will * be "current" except in the case of requeue pi. * @set_waiters: force setting the FUTEX_WAITERS bit (1) or not (0) |
1a52084d0 futex: split out ... |
830 |
* |
6c23cbbd5 futex: fix kernel... |
831 832 833 |
* Return: * 0 - ready to wait; * 1 - acquired the lock; |
1a52084d0 futex: split out ... |
834 835 836 837 838 839 840 |
* <0 - error * * The hb->lock and futex_key refs shall be held by the caller. */ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb, union futex_key *key, struct futex_pi_state **ps, |
bab5bc9e8 futex: fixup unlo... |
841 |
struct task_struct *task, int set_waiters) |
1a52084d0 futex: split out ... |
842 |
{ |
59fa62451 futex: Handle fut... |
843 |
int lock_taken, ret, force_take = 0; |
c0c9ed150 futex: Avoid redu... |
844 |
u32 uval, newval, curval, vpid = task_pid_vnr(task); |
1a52084d0 futex: split out ... |
845 846 847 848 849 850 851 852 853 |
retry: ret = lock_taken = 0; /* * To avoid races, we attempt to take the lock here again * (by doing a 0 -> TID atomic cmpxchg), while holding all * the locks. It will most likely not succeed. */ |
c0c9ed150 futex: Avoid redu... |
854 |
newval = vpid; |
bab5bc9e8 futex: fixup unlo... |
855 856 |
if (set_waiters) newval |= FUTEX_WAITERS; |
1a52084d0 futex: split out ... |
857 |
|
37a9d912b futex: Sanitize c... |
858 |
if (unlikely(cmpxchg_futex_value_locked(&curval, uaddr, 0, newval))) |
1a52084d0 futex: split out ... |
859 860 861 862 863 |
return -EFAULT; /* * Detect deadlocks. */ |
c0c9ed150 futex: Avoid redu... |
864 |
if ((unlikely((curval & FUTEX_TID_MASK) == vpid))) |
1a52084d0 futex: split out ... |
865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 |
return -EDEADLK; /* * Surprise - we got the lock. Just return to userspace: */ if (unlikely(!curval)) return 1; uval = curval; /* * Set the FUTEX_WAITERS flag, so the owner will know it has someone * to wake at the next unlock. */ newval = curval | FUTEX_WAITERS; /* |
59fa62451 futex: Handle fut... |
882 |
* Should we force take the futex? See below. |
1a52084d0 futex: split out ... |
883 |
*/ |
59fa62451 futex: Handle fut... |
884 885 886 887 888 |
if (unlikely(force_take)) { /* * Keep the OWNER_DIED and the WAITERS bit and set the * new TID value. */ |
c0c9ed150 futex: Avoid redu... |
889 |
newval = (curval & ~FUTEX_TID_MASK) | vpid; |
59fa62451 futex: Handle fut... |
890 |
force_take = 0; |
1a52084d0 futex: split out ... |
891 892 |
lock_taken = 1; } |
37a9d912b futex: Sanitize c... |
893 |
if (unlikely(cmpxchg_futex_value_locked(&curval, uaddr, uval, newval))) |
1a52084d0 futex: split out ... |
894 895 896 897 898 |
return -EFAULT; if (unlikely(curval != uval)) goto retry; /* |
59fa62451 futex: Handle fut... |
899 |
* We took the lock due to forced take over. |
1a52084d0 futex: split out ... |
900 901 902 903 904 905 906 907 908 909 910 911 912 913 |
*/ if (unlikely(lock_taken)) return 1; /* * We dont have the lock. Look up the PI state (or create it if * we are the first waiter): */ ret = lookup_pi_state(uval, hb, key, ps); if (unlikely(ret)) { switch (ret) { case -ESRCH: /* |
59fa62451 futex: Handle fut... |
914 915 916 917 918 919 920 921 |
* We failed to find an owner for this * futex. So we have no pi_state to block * on. This can happen in two cases: * * 1) The owner died * 2) A stale FUTEX_WAITERS bit * * Re-read the futex value. |
1a52084d0 futex: split out ... |
922 923 924 925 926 |
*/ if (get_futex_value_locked(&curval, uaddr)) return -EFAULT; /* |
59fa62451 futex: Handle fut... |
927 928 929 |
* If the owner died or we have a stale * WAITERS bit the owner TID in the user space * futex is 0. |
1a52084d0 futex: split out ... |
930 |
*/ |
59fa62451 futex: Handle fut... |
931 932 |
if (!(curval & FUTEX_TID_MASK)) { force_take = 1; |
1a52084d0 futex: split out ... |
933 934 935 936 937 938 939 940 941 |
goto retry; } default: break; } } return ret; } |
2e12978a9 futex,plist: Pass... |
942 943 944 945 946 947 948 949 950 |
/** * __unqueue_futex() - Remove the futex_q from its futex_hash_bucket * @q: The futex_q to unqueue * * The q->lock_ptr must not be NULL and must be held by the caller. */ static void __unqueue_futex(struct futex_q *q) { struct futex_hash_bucket *hb; |
290962021 futex: Fix WARN_O... |
951 952 |
if (WARN_ON_SMP(!q->lock_ptr || !spin_is_locked(q->lock_ptr)) || WARN_ON(plist_node_empty(&q->list))) |
2e12978a9 futex,plist: Pass... |
953 954 955 956 |
return; hb = container_of(q->lock_ptr, struct futex_hash_bucket, lock); plist_del(&q->list, &hb->chain); |
11d4616bd futex: revert bac... |
957 |
hb_waiters_dec(hb); |
2e12978a9 futex,plist: Pass... |
958 |
} |
c87e2837b [PATCH] pi-futex:... |
959 |
/* |
1da177e4c Linux-2.6.12-rc2 |
960 961 962 963 964 |
* The hash bucket lock must be held when this is called. * Afterwards, the futex_q must not be accessed. */ static void wake_futex(struct futex_q *q) { |
f1a11e057 futex: remove the... |
965 |
struct task_struct *p = q->task; |
aa10990e0 futex: avoid wake... |
966 967 968 |
if (WARN(q->pi_state || q->rt_waiter, "refusing to wake PI futex ")) return; |
1da177e4c Linux-2.6.12-rc2 |
969 |
/* |
f1a11e057 futex: remove the... |
970 |
* We set q->lock_ptr = NULL _before_ we wake up the task. If |
fb62db2ba futex: Fix kernel... |
971 972 |
* a non-futex wake up happens on another CPU then the task * might exit and p would dereference a non-existing task |
f1a11e057 futex: remove the... |
973 974 |
* struct. Prevent this by holding a reference on p across the * wake up. |
1da177e4c Linux-2.6.12-rc2 |
975 |
*/ |
f1a11e057 futex: remove the... |
976 |
get_task_struct(p); |
2e12978a9 futex,plist: Pass... |
977 |
__unqueue_futex(q); |
1da177e4c Linux-2.6.12-rc2 |
978 |
/* |
f1a11e057 futex: remove the... |
979 980 981 982 |
* The waiting task can free the futex_q as soon as * q->lock_ptr = NULL is written, without taking any locks. A * memory barrier is required here to prevent the following * store to lock_ptr from getting ahead of the plist_del. |
1da177e4c Linux-2.6.12-rc2 |
983 |
*/ |
ccdea2f88 [PATCH] futex: re... |
984 |
smp_wmb(); |
1da177e4c Linux-2.6.12-rc2 |
985 |
q->lock_ptr = NULL; |
f1a11e057 futex: remove the... |
986 987 988 |
wake_up_state(p, TASK_NORMAL); put_task_struct(p); |
1da177e4c Linux-2.6.12-rc2 |
989 |
} |
c87e2837b [PATCH] pi-futex:... |
990 991 992 993 |
static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this) { struct task_struct *new_owner; struct futex_pi_state *pi_state = this->pi_state; |
7cfdaf38d futex: uninitiali... |
994 |
u32 uninitialized_var(curval), newval; |
c87e2837b [PATCH] pi-futex:... |
995 996 997 |
if (!pi_state) return -EINVAL; |
51246bfd1 futex: Handle use... |
998 999 1000 1001 1002 1003 |
/* * If current does not own the pi_state then the futex is * inconsistent and user space fiddled with the futex value. */ if (pi_state->owner != current) return -EINVAL; |
d209d74d5 rtmutes: Convert ... |
1004 |
raw_spin_lock(&pi_state->pi_mutex.wait_lock); |
c87e2837b [PATCH] pi-futex:... |
1005 1006 1007 |
new_owner = rt_mutex_next_owner(&pi_state->pi_mutex); /* |
f123c98e7 rtmutex: Fix comm... |
1008 1009 1010 |
* It is possible that the next waiter (the one that brought * this owner to the kernel) timed out and is no longer * waiting on the lock. |
c87e2837b [PATCH] pi-futex:... |
1011 1012 1013 1014 1015 1016 1017 1018 1019 |
*/ if (!new_owner) new_owner = this->task; /* * We pass it to the next owner. (The WAITERS bit is always * kept enabled while there is PI state around. We must also * preserve the owner died bit.) */ |
e3f2ddeac [PATCH] pi-futex:... |
1020 |
if (!(uval & FUTEX_OWNER_DIED)) { |
778e9a9c3 pi-futex: fix exi... |
1021 |
int ret = 0; |
b488893a3 pid namespaces: c... |
1022 |
newval = FUTEX_WAITERS | task_pid_vnr(new_owner); |
e3f2ddeac [PATCH] pi-futex:... |
1023 |
|
37a9d912b futex: Sanitize c... |
1024 |
if (cmpxchg_futex_value_locked(&curval, uaddr, uval, newval)) |
778e9a9c3 pi-futex: fix exi... |
1025 |
ret = -EFAULT; |
cde898fa8 futex: correctly ... |
1026 |
else if (curval != uval) |
778e9a9c3 pi-futex: fix exi... |
1027 1028 |
ret = -EINVAL; if (ret) { |
d209d74d5 rtmutes: Convert ... |
1029 |
raw_spin_unlock(&pi_state->pi_mutex.wait_lock); |
778e9a9c3 pi-futex: fix exi... |
1030 1031 |
return ret; } |
e3f2ddeac [PATCH] pi-futex:... |
1032 |
} |
c87e2837b [PATCH] pi-futex:... |
1033 |
|
1d6154825 sched: Convert pi... |
1034 |
raw_spin_lock_irq(&pi_state->owner->pi_lock); |
627371d73 [PATCH] pi-futex:... |
1035 1036 |
WARN_ON(list_empty(&pi_state->list)); list_del_init(&pi_state->list); |
1d6154825 sched: Convert pi... |
1037 |
raw_spin_unlock_irq(&pi_state->owner->pi_lock); |
627371d73 [PATCH] pi-futex:... |
1038 |
|
1d6154825 sched: Convert pi... |
1039 |
raw_spin_lock_irq(&new_owner->pi_lock); |
627371d73 [PATCH] pi-futex:... |
1040 |
WARN_ON(!list_empty(&pi_state->list)); |
c87e2837b [PATCH] pi-futex:... |
1041 1042 |
list_add(&pi_state->list, &new_owner->pi_state_list); pi_state->owner = new_owner; |
1d6154825 sched: Convert pi... |
1043 |
raw_spin_unlock_irq(&new_owner->pi_lock); |
627371d73 [PATCH] pi-futex:... |
1044 |
|
d209d74d5 rtmutes: Convert ... |
1045 |
raw_spin_unlock(&pi_state->pi_mutex.wait_lock); |
c87e2837b [PATCH] pi-futex:... |
1046 1047 1048 1049 1050 1051 1052 |
rt_mutex_unlock(&pi_state->pi_mutex); return 0; } static int unlock_futex_pi(u32 __user *uaddr, u32 uval) { |
7cfdaf38d futex: uninitiali... |
1053 |
u32 uninitialized_var(oldval); |
c87e2837b [PATCH] pi-futex:... |
1054 1055 1056 1057 1058 |
/* * There is no waiter, so we unlock the futex. The owner died * bit has not to be preserved here. We are the owner: */ |
37a9d912b futex: Sanitize c... |
1059 1060 |
if (cmpxchg_futex_value_locked(&oldval, uaddr, uval, 0)) return -EFAULT; |
c87e2837b [PATCH] pi-futex:... |
1061 1062 1063 1064 1065 |
if (oldval != uval) return -EAGAIN; return 0; } |
1da177e4c Linux-2.6.12-rc2 |
1066 |
/* |
8b8f319fc [PATCH] lockdep: ... |
1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 |
* Express the locking dependencies for lockdep: */ static inline void double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2) { if (hb1 <= hb2) { spin_lock(&hb1->lock); if (hb1 < hb2) spin_lock_nested(&hb2->lock, SINGLE_DEPTH_NESTING); } else { /* hb1 > hb2 */ spin_lock(&hb2->lock); spin_lock_nested(&hb1->lock, SINGLE_DEPTH_NESTING); } } |
5eb3dc62f futex: add double... |
1081 1082 1083 |
static inline void double_unlock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2) { |
f061d3515 futex: remove the... |
1084 |
spin_unlock(&hb1->lock); |
88f502fed futex: remove the... |
1085 1086 |
if (hb1 != hb2) spin_unlock(&hb2->lock); |
5eb3dc62f futex: add double... |
1087 |
} |
8b8f319fc [PATCH] lockdep: ... |
1088 |
/* |
b2d0994b1 futex: update fut... |
1089 |
* Wake up waiters matching bitset queued on this futex (uaddr). |
1da177e4c Linux-2.6.12-rc2 |
1090 |
*/ |
b41277dc7 futex: Replace fs... |
1091 1092 |
static int futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset) |
1da177e4c Linux-2.6.12-rc2 |
1093 |
{ |
e2970f2fb [PATCH] pi-futex:... |
1094 |
struct futex_hash_bucket *hb; |
1da177e4c Linux-2.6.12-rc2 |
1095 |
struct futex_q *this, *next; |
38d47c1b7 futex: rely on ge... |
1096 |
union futex_key key = FUTEX_KEY_INIT; |
1da177e4c Linux-2.6.12-rc2 |
1097 |
int ret; |
cd689985c futex: Add bitset... |
1098 1099 |
if (!bitset) return -EINVAL; |
9ea71503a futex: Fix regres... |
1100 |
ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, VERIFY_READ); |
1da177e4c Linux-2.6.12-rc2 |
1101 1102 |
if (unlikely(ret != 0)) goto out; |
e2970f2fb [PATCH] pi-futex:... |
1103 |
hb = hash_futex(&key); |
b0c29f79e futexes: Avoid ta... |
1104 1105 1106 1107 |
/* Make sure we really have tasks to wakeup */ if (!hb_waiters_pending(hb)) goto out_put_key; |
e2970f2fb [PATCH] pi-futex:... |
1108 |
spin_lock(&hb->lock); |
1da177e4c Linux-2.6.12-rc2 |
1109 |
|
0d00c7b20 futexes: Clean up... |
1110 |
plist_for_each_entry_safe(this, next, &hb->chain, list) { |
1da177e4c Linux-2.6.12-rc2 |
1111 |
if (match_futex (&this->key, &key)) { |
52400ba94 futex: add requeu... |
1112 |
if (this->pi_state || this->rt_waiter) { |
ed6f7b10e [PATCH] pi-futex:... |
1113 1114 1115 |
ret = -EINVAL; break; } |
cd689985c futex: Add bitset... |
1116 1117 1118 1119 |
/* Check if one of the bits is set in both bitsets */ if (!(this->bitset & bitset)) continue; |
1da177e4c Linux-2.6.12-rc2 |
1120 1121 1122 1123 1124 |
wake_futex(this); if (++ret >= nr_wake) break; } } |
e2970f2fb [PATCH] pi-futex:... |
1125 |
spin_unlock(&hb->lock); |
b0c29f79e futexes: Avoid ta... |
1126 |
out_put_key: |
ae791a2d2 futex: Cleanup st... |
1127 |
put_futex_key(&key); |
42d35d48c futex: make futex... |
1128 |
out: |
1da177e4c Linux-2.6.12-rc2 |
1129 1130 1131 1132 |
return ret; } /* |
4732efbeb [PATCH] FUTEX_WAK... |
1133 1134 1135 |
* Wake up all waiters hashed on the physical page that is mapped * to this virtual address: */ |
e2970f2fb [PATCH] pi-futex:... |
1136 |
static int |
b41277dc7 futex: Replace fs... |
1137 |
futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2, |
e2970f2fb [PATCH] pi-futex:... |
1138 |
int nr_wake, int nr_wake2, int op) |
4732efbeb [PATCH] FUTEX_WAK... |
1139 |
{ |
38d47c1b7 futex: rely on ge... |
1140 |
union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT; |
e2970f2fb [PATCH] pi-futex:... |
1141 |
struct futex_hash_bucket *hb1, *hb2; |
4732efbeb [PATCH] FUTEX_WAK... |
1142 |
struct futex_q *this, *next; |
e4dc5b7a3 futex: clean up f... |
1143 |
int ret, op_ret; |
4732efbeb [PATCH] FUTEX_WAK... |
1144 |
|
e4dc5b7a3 futex: clean up f... |
1145 |
retry: |
9ea71503a futex: Fix regres... |
1146 |
ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ); |
4732efbeb [PATCH] FUTEX_WAK... |
1147 1148 |
if (unlikely(ret != 0)) goto out; |
9ea71503a futex: Fix regres... |
1149 |
ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE); |
4732efbeb [PATCH] FUTEX_WAK... |
1150 |
if (unlikely(ret != 0)) |
42d35d48c futex: make futex... |
1151 |
goto out_put_key1; |
4732efbeb [PATCH] FUTEX_WAK... |
1152 |
|
e2970f2fb [PATCH] pi-futex:... |
1153 1154 |
hb1 = hash_futex(&key1); hb2 = hash_futex(&key2); |
4732efbeb [PATCH] FUTEX_WAK... |
1155 |
|
e4dc5b7a3 futex: clean up f... |
1156 |
retry_private: |
eaaea8036 futex: Fix lockin... |
1157 |
double_lock_hb(hb1, hb2); |
e2970f2fb [PATCH] pi-futex:... |
1158 |
op_ret = futex_atomic_op_inuser(op, uaddr2); |
4732efbeb [PATCH] FUTEX_WAK... |
1159 |
if (unlikely(op_ret < 0)) { |
4732efbeb [PATCH] FUTEX_WAK... |
1160 |
|
5eb3dc62f futex: add double... |
1161 |
double_unlock_hb(hb1, hb2); |
4732efbeb [PATCH] FUTEX_WAK... |
1162 |
|
7ee1dd3fe [PATCH] FRV: Make... |
1163 |
#ifndef CONFIG_MMU |
e2970f2fb [PATCH] pi-futex:... |
1164 1165 1166 1167 |
/* * we don't get EFAULT from MMU faults if we don't have an MMU, * but we might get them from range checking */ |
7ee1dd3fe [PATCH] FRV: Make... |
1168 |
ret = op_ret; |
42d35d48c futex: make futex... |
1169 |
goto out_put_keys; |
7ee1dd3fe [PATCH] FRV: Make... |
1170 |
#endif |
796f8d9b9 [PATCH] FUTEX_WAK... |
1171 1172 |
if (unlikely(op_ret != -EFAULT)) { ret = op_ret; |
42d35d48c futex: make futex... |
1173 |
goto out_put_keys; |
796f8d9b9 [PATCH] FUTEX_WAK... |
1174 |
} |
d0725992c futex: Fix the wr... |
1175 |
ret = fault_in_user_writeable(uaddr2); |
4732efbeb [PATCH] FUTEX_WAK... |
1176 |
if (ret) |
de87fcc12 futex: additional... |
1177 |
goto out_put_keys; |
4732efbeb [PATCH] FUTEX_WAK... |
1178 |
|
b41277dc7 futex: Replace fs... |
1179 |
if (!(flags & FLAGS_SHARED)) |
e4dc5b7a3 futex: clean up f... |
1180 |
goto retry_private; |
ae791a2d2 futex: Cleanup st... |
1181 1182 |
put_futex_key(&key2); put_futex_key(&key1); |
e4dc5b7a3 futex: clean up f... |
1183 |
goto retry; |
4732efbeb [PATCH] FUTEX_WAK... |
1184 |
} |
0d00c7b20 futexes: Clean up... |
1185 |
plist_for_each_entry_safe(this, next, &hb1->chain, list) { |
4732efbeb [PATCH] FUTEX_WAK... |
1186 |
if (match_futex (&this->key, &key1)) { |
aa10990e0 futex: avoid wake... |
1187 1188 1189 1190 |
if (this->pi_state || this->rt_waiter) { ret = -EINVAL; goto out_unlock; } |
4732efbeb [PATCH] FUTEX_WAK... |
1191 1192 1193 1194 1195 1196 1197 |
wake_futex(this); if (++ret >= nr_wake) break; } } if (op_ret > 0) { |
4732efbeb [PATCH] FUTEX_WAK... |
1198 |
op_ret = 0; |
0d00c7b20 futexes: Clean up... |
1199 |
plist_for_each_entry_safe(this, next, &hb2->chain, list) { |
4732efbeb [PATCH] FUTEX_WAK... |
1200 |
if (match_futex (&this->key, &key2)) { |
aa10990e0 futex: avoid wake... |
1201 1202 1203 1204 |
if (this->pi_state || this->rt_waiter) { ret = -EINVAL; goto out_unlock; } |
4732efbeb [PATCH] FUTEX_WAK... |
1205 1206 1207 1208 1209 1210 1211 |
wake_futex(this); if (++op_ret >= nr_wake2) break; } } ret += op_ret; } |
aa10990e0 futex: avoid wake... |
1212 |
out_unlock: |
5eb3dc62f futex: add double... |
1213 |
double_unlock_hb(hb1, hb2); |
42d35d48c futex: make futex... |
1214 |
out_put_keys: |
ae791a2d2 futex: Cleanup st... |
1215 |
put_futex_key(&key2); |
42d35d48c futex: make futex... |
1216 |
out_put_key1: |
ae791a2d2 futex: Cleanup st... |
1217 |
put_futex_key(&key1); |
42d35d48c futex: make futex... |
1218 |
out: |
4732efbeb [PATCH] FUTEX_WAK... |
1219 1220 |
return ret; } |
9121e4783 futex: distangle ... |
1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 |
/** * requeue_futex() - Requeue a futex_q from one hb to another * @q: the futex_q to requeue * @hb1: the source hash_bucket * @hb2: the target hash_bucket * @key2: the new key for the requeued futex_q */ static inline void requeue_futex(struct futex_q *q, struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2, union futex_key *key2) { /* * If key1 and key2 hash to the same bucket, no need to * requeue. */ if (likely(&hb1->chain != &hb2->chain)) { plist_del(&q->list, &hb1->chain); |
11d4616bd futex: revert bac... |
1239 |
hb_waiters_dec(hb1); |
9121e4783 futex: distangle ... |
1240 |
plist_add(&q->list, &hb2->chain); |
11d4616bd futex: revert bac... |
1241 |
hb_waiters_inc(hb2); |
9121e4783 futex: distangle ... |
1242 |
q->lock_ptr = &hb2->lock; |
9121e4783 futex: distangle ... |
1243 1244 1245 1246 |
} get_futex_key_refs(key2); q->key = *key2; } |
52400ba94 futex: add requeu... |
1247 1248 |
/** * requeue_pi_wake_futex() - Wake a task that acquired the lock during requeue |
d96ee56ce futex: Make funct... |
1249 1250 1251 |
* @q: the futex_q * @key: the key of the requeue target futex * @hb: the hash_bucket of the requeue target futex |
52400ba94 futex: add requeu... |
1252 1253 1254 1255 1256 |
* * During futex_requeue, with requeue_pi=1, it is possible to acquire the * target futex if it is uncontended or via a lock steal. Set the futex_q key * to the requeue target futex so the waiter can detect the wakeup on the right * futex, but remove it from the hb and NULL the rt_waiter so it can detect |
beda2c7ea futex: Update fut... |
1257 1258 1259 |
* atomic lock acquisition. Set the q->lock_ptr to the requeue target hb->lock * to protect access to the pi_state to fixup the owner later. Must be called * with both q->lock_ptr and hb->lock held. |
52400ba94 futex: add requeu... |
1260 1261 |
*/ static inline |
beda2c7ea futex: Update fut... |
1262 1263 |
void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key, struct futex_hash_bucket *hb) |
52400ba94 futex: add requeu... |
1264 |
{ |
52400ba94 futex: add requeu... |
1265 1266 |
get_futex_key_refs(key); q->key = *key; |
2e12978a9 futex,plist: Pass... |
1267 |
__unqueue_futex(q); |
52400ba94 futex: add requeu... |
1268 1269 1270 |
WARN_ON(!q->rt_waiter); q->rt_waiter = NULL; |
beda2c7ea futex: Update fut... |
1271 |
q->lock_ptr = &hb->lock; |
beda2c7ea futex: Update fut... |
1272 |
|
f1a11e057 futex: remove the... |
1273 |
wake_up_state(q->task, TASK_NORMAL); |
52400ba94 futex: add requeu... |
1274 1275 1276 1277 |
} /** * futex_proxy_trylock_atomic() - Attempt an atomic lock for the top waiter |
bab5bc9e8 futex: fixup unlo... |
1278 1279 1280 1281 1282 1283 1284 |
* @pifutex: the user address of the to futex * @hb1: the from futex hash bucket, must be locked by the caller * @hb2: the to futex hash bucket, must be locked by the caller * @key1: the from futex key * @key2: the to futex key * @ps: address to store the pi_state pointer * @set_waiters: force setting the FUTEX_WAITERS bit (1) or not (0) |
52400ba94 futex: add requeu... |
1285 1286 |
* * Try and get the lock on behalf of the top waiter if we can do it atomically. |
bab5bc9e8 futex: fixup unlo... |
1287 1288 1289 |
* Wake the top waiter if we succeed. If the caller specified set_waiters, * then direct futex_lock_pi_atomic() to force setting the FUTEX_WAITERS bit. * hb1 and hb2 must be held by the caller. |
52400ba94 futex: add requeu... |
1290 |
* |
6c23cbbd5 futex: fix kernel... |
1291 1292 1293 |
* Return: * 0 - failed to acquire the lock atomically; * 1 - acquired the lock; |
52400ba94 futex: add requeu... |
1294 1295 1296 1297 1298 1299 |
* <0 - error */ static int futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2, union futex_key *key1, union futex_key *key2, |
bab5bc9e8 futex: fixup unlo... |
1300 |
struct futex_pi_state **ps, int set_waiters) |
52400ba94 futex: add requeu... |
1301 |
{ |
bab5bc9e8 futex: fixup unlo... |
1302 |
struct futex_q *top_waiter = NULL; |
52400ba94 futex: add requeu... |
1303 1304 1305 1306 1307 |
u32 curval; int ret; if (get_futex_value_locked(&curval, pifutex)) return -EFAULT; |
bab5bc9e8 futex: fixup unlo... |
1308 1309 1310 1311 1312 1313 1314 1315 |
/* * Find the top_waiter and determine if there are additional waiters. * If the caller intends to requeue more than 1 waiter to pifutex, * force futex_lock_pi_atomic() to set the FUTEX_WAITERS bit now, * as we have means to handle the possible fault. If not, don't set * the bit unecessarily as it will force the subsequent unlock to enter * the kernel. */ |
52400ba94 futex: add requeu... |
1316 1317 1318 1319 1320 |
top_waiter = futex_top_waiter(hb1, key1); /* There are no waiters, nothing for us to do. */ if (!top_waiter) return 0; |
84bc4af59 futex: Detect mis... |
1321 1322 1323 |
/* Ensure we requeue to the expected futex. */ if (!match_futex(top_waiter->requeue_pi_key, key2)) return -EINVAL; |
52400ba94 futex: add requeu... |
1324 |
/* |
bab5bc9e8 futex: fixup unlo... |
1325 1326 1327 |
* Try to take the lock for top_waiter. Set the FUTEX_WAITERS bit in * the contended case or if set_waiters is 1. The pi_state is returned * in ps in contended cases. |
52400ba94 futex: add requeu... |
1328 |
*/ |
bab5bc9e8 futex: fixup unlo... |
1329 1330 |
ret = futex_lock_pi_atomic(pifutex, hb2, key2, ps, top_waiter->task, set_waiters); |
52400ba94 futex: add requeu... |
1331 |
if (ret == 1) |
beda2c7ea futex: Update fut... |
1332 |
requeue_pi_wake_futex(top_waiter, key2, hb2); |
52400ba94 futex: add requeu... |
1333 1334 1335 1336 1337 1338 |
return ret; } /** * futex_requeue() - Requeue waiters from uaddr1 to uaddr2 |
fb62db2ba futex: Fix kernel... |
1339 |
* @uaddr1: source futex user address |
b41277dc7 futex: Replace fs... |
1340 |
* @flags: futex flags (FLAGS_SHARED, etc.) |
fb62db2ba futex: Fix kernel... |
1341 1342 1343 1344 1345 |
* @uaddr2: target futex user address * @nr_wake: number of waiters to wake (must be 1 for requeue_pi) * @nr_requeue: number of waiters to requeue (0-INT_MAX) * @cmpval: @uaddr1 expected value (or %NULL) * @requeue_pi: if we are attempting to requeue from a non-pi futex to a |
b41277dc7 futex: Replace fs... |
1346 |
* pi futex (pi to pi requeue is not supported) |
52400ba94 futex: add requeu... |
1347 1348 1349 1350 |
* * Requeue waiters on uaddr1 to uaddr2. In the requeue_pi case, try to acquire * uaddr2 atomically on behalf of the top waiter. * |
6c23cbbd5 futex: fix kernel... |
1351 1352 |
* Return: * >=0 - on success, the number of tasks requeued or woken; |
52400ba94 futex: add requeu... |
1353 |
* <0 - on error |
1da177e4c Linux-2.6.12-rc2 |
1354 |
*/ |
b41277dc7 futex: Replace fs... |
1355 1356 1357 |
static int futex_requeue(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2, int nr_wake, int nr_requeue, u32 *cmpval, int requeue_pi) |
1da177e4c Linux-2.6.12-rc2 |
1358 |
{ |
38d47c1b7 futex: rely on ge... |
1359 |
union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT; |
52400ba94 futex: add requeu... |
1360 1361 |
int drop_count = 0, task_count = 0, ret; struct futex_pi_state *pi_state = NULL; |
e2970f2fb [PATCH] pi-futex:... |
1362 |
struct futex_hash_bucket *hb1, *hb2; |
1da177e4c Linux-2.6.12-rc2 |
1363 |
struct futex_q *this, *next; |
52400ba94 futex: add requeu... |
1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 |
u32 curval2; if (requeue_pi) { /* * requeue_pi requires a pi_state, try to allocate it now * without any locks in case it fails. */ if (refill_pi_state_cache()) return -ENOMEM; /* * requeue_pi must wake as many tasks as it can, up to nr_wake * + nr_requeue, since it acquires the rt_mutex prior to * returning to userspace, so as to not leave the rt_mutex with * waiters and no owner. However, second and third wake-ups * cannot be predicted as they involve race conditions with the * first wake and a fault while looking up the pi_state. Both * pthread_cond_signal() and pthread_cond_broadcast() should * use nr_wake=1. */ if (nr_wake != 1) return -EINVAL; } |
1da177e4c Linux-2.6.12-rc2 |
1386 |
|
42d35d48c futex: make futex... |
1387 |
retry: |
52400ba94 futex: add requeu... |
1388 1389 1390 1391 1392 1393 1394 1395 |
if (pi_state != NULL) { /* * We will have to lookup the pi_state again, so free this one * to keep the accounting correct. */ free_pi_state(pi_state); pi_state = NULL; } |
9ea71503a futex: Fix regres... |
1396 |
ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ); |
1da177e4c Linux-2.6.12-rc2 |
1397 1398 |
if (unlikely(ret != 0)) goto out; |
9ea71503a futex: Fix regres... |
1399 1400 |
ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, requeue_pi ? VERIFY_WRITE : VERIFY_READ); |
1da177e4c Linux-2.6.12-rc2 |
1401 |
if (unlikely(ret != 0)) |
42d35d48c futex: make futex... |
1402 |
goto out_put_key1; |
1da177e4c Linux-2.6.12-rc2 |
1403 |
|
e2970f2fb [PATCH] pi-futex:... |
1404 1405 |
hb1 = hash_futex(&key1); hb2 = hash_futex(&key2); |
1da177e4c Linux-2.6.12-rc2 |
1406 |
|
e4dc5b7a3 futex: clean up f... |
1407 |
retry_private: |
69cd9eba3 futex: avoid race... |
1408 |
hb_waiters_inc(hb2); |
8b8f319fc [PATCH] lockdep: ... |
1409 |
double_lock_hb(hb1, hb2); |
1da177e4c Linux-2.6.12-rc2 |
1410 |
|
e2970f2fb [PATCH] pi-futex:... |
1411 1412 |
if (likely(cmpval != NULL)) { u32 curval; |
1da177e4c Linux-2.6.12-rc2 |
1413 |
|
e2970f2fb [PATCH] pi-futex:... |
1414 |
ret = get_futex_value_locked(&curval, uaddr1); |
1da177e4c Linux-2.6.12-rc2 |
1415 1416 |
if (unlikely(ret)) { |
5eb3dc62f futex: add double... |
1417 |
double_unlock_hb(hb1, hb2); |
69cd9eba3 futex: avoid race... |
1418 |
hb_waiters_dec(hb2); |
1da177e4c Linux-2.6.12-rc2 |
1419 |
|
e2970f2fb [PATCH] pi-futex:... |
1420 |
ret = get_user(curval, uaddr1); |
e4dc5b7a3 futex: clean up f... |
1421 1422 |
if (ret) goto out_put_keys; |
1da177e4c Linux-2.6.12-rc2 |
1423 |
|
b41277dc7 futex: Replace fs... |
1424 |
if (!(flags & FLAGS_SHARED)) |
e4dc5b7a3 futex: clean up f... |
1425 |
goto retry_private; |
1da177e4c Linux-2.6.12-rc2 |
1426 |
|
ae791a2d2 futex: Cleanup st... |
1427 1428 |
put_futex_key(&key2); put_futex_key(&key1); |
e4dc5b7a3 futex: clean up f... |
1429 |
goto retry; |
1da177e4c Linux-2.6.12-rc2 |
1430 |
} |
e2970f2fb [PATCH] pi-futex:... |
1431 |
if (curval != *cmpval) { |
1da177e4c Linux-2.6.12-rc2 |
1432 1433 1434 1435 |
ret = -EAGAIN; goto out_unlock; } } |
52400ba94 futex: add requeu... |
1436 |
if (requeue_pi && (task_count - nr_wake < nr_requeue)) { |
bab5bc9e8 futex: fixup unlo... |
1437 1438 1439 1440 1441 1442 |
/* * Attempt to acquire uaddr2 and wake the top waiter. If we * intend to requeue waiters, force setting the FUTEX_WAITERS * bit. We force this here where we are able to easily handle * faults rather in the requeue loop below. */ |
52400ba94 futex: add requeu... |
1443 |
ret = futex_proxy_trylock_atomic(uaddr2, hb1, hb2, &key1, |
bab5bc9e8 futex: fixup unlo... |
1444 |
&key2, &pi_state, nr_requeue); |
52400ba94 futex: add requeu... |
1445 1446 1447 1448 1449 1450 1451 1452 1453 |
/* * At this point the top_waiter has either taken uaddr2 or is * waiting on it. If the former, then the pi_state will not * exist yet, look it up one more time to ensure we have a * reference to it. */ if (ret == 1) { WARN_ON(pi_state); |
89061d3d5 futex: Move drop_... |
1454 |
drop_count++; |
52400ba94 futex: add requeu... |
1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 |
task_count++; ret = get_futex_value_locked(&curval2, uaddr2); if (!ret) ret = lookup_pi_state(curval2, hb2, &key2, &pi_state); } switch (ret) { case 0: break; case -EFAULT: double_unlock_hb(hb1, hb2); |
69cd9eba3 futex: avoid race... |
1467 |
hb_waiters_dec(hb2); |
ae791a2d2 futex: Cleanup st... |
1468 1469 |
put_futex_key(&key2); put_futex_key(&key1); |
d0725992c futex: Fix the wr... |
1470 |
ret = fault_in_user_writeable(uaddr2); |
52400ba94 futex: add requeu... |
1471 1472 1473 1474 1475 1476 |
if (!ret) goto retry; goto out; case -EAGAIN: /* The owner was exiting, try again. */ double_unlock_hb(hb1, hb2); |
69cd9eba3 futex: avoid race... |
1477 |
hb_waiters_dec(hb2); |
ae791a2d2 futex: Cleanup st... |
1478 1479 |
put_futex_key(&key2); put_futex_key(&key1); |
52400ba94 futex: add requeu... |
1480 1481 1482 1483 1484 1485 |
cond_resched(); goto retry; default: goto out_unlock; } } |
0d00c7b20 futexes: Clean up... |
1486 |
plist_for_each_entry_safe(this, next, &hb1->chain, list) { |
52400ba94 futex: add requeu... |
1487 1488 1489 1490 |
if (task_count - nr_wake >= nr_requeue) break; if (!match_futex(&this->key, &key1)) |
1da177e4c Linux-2.6.12-rc2 |
1491 |
continue; |
52400ba94 futex: add requeu... |
1492 |
|
392741e0a futex: Fix handli... |
1493 1494 1495 |
/* * FUTEX_WAIT_REQEUE_PI and FUTEX_CMP_REQUEUE_PI should always * be paired with each other and no other futex ops. |
aa10990e0 futex: avoid wake... |
1496 1497 1498 |
* * We should never be requeueing a futex_q with a pi_state, * which is awaiting a futex_unlock_pi(). |
392741e0a futex: Fix handli... |
1499 1500 |
*/ if ((requeue_pi && !this->rt_waiter) || |
aa10990e0 futex: avoid wake... |
1501 1502 |
(!requeue_pi && this->rt_waiter) || this->pi_state) { |
392741e0a futex: Fix handli... |
1503 1504 1505 |
ret = -EINVAL; break; } |
52400ba94 futex: add requeu... |
1506 1507 1508 1509 1510 1511 1512 |
/* * Wake nr_wake waiters. For requeue_pi, if we acquired the * lock, we already woke the top_waiter. If not, it will be * woken by futex_unlock_pi(). */ if (++task_count <= nr_wake && !requeue_pi) { |
1da177e4c Linux-2.6.12-rc2 |
1513 |
wake_futex(this); |
52400ba94 futex: add requeu... |
1514 1515 |
continue; } |
1da177e4c Linux-2.6.12-rc2 |
1516 |
|
84bc4af59 futex: Detect mis... |
1517 1518 1519 1520 1521 |
/* Ensure we requeue to the expected futex for requeue_pi. */ if (requeue_pi && !match_futex(this->requeue_pi_key, &key2)) { ret = -EINVAL; break; } |
52400ba94 futex: add requeu... |
1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 |
/* * Requeue nr_requeue waiters and possibly one more in the case * of requeue_pi if we couldn't acquire the lock atomically. */ if (requeue_pi) { /* Prepare the waiter to take the rt_mutex. */ atomic_inc(&pi_state->refcount); this->pi_state = pi_state; ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex, this->rt_waiter, this->task, 1); if (ret == 1) { /* We got the lock. */ |
beda2c7ea futex: Update fut... |
1535 |
requeue_pi_wake_futex(this, &key2, hb2); |
89061d3d5 futex: Move drop_... |
1536 |
drop_count++; |
52400ba94 futex: add requeu... |
1537 1538 1539 1540 1541 1542 1543 |
continue; } else if (ret) { /* -EDEADLK */ this->pi_state = NULL; free_pi_state(pi_state); goto out_unlock; } |
1da177e4c Linux-2.6.12-rc2 |
1544 |
} |
52400ba94 futex: add requeu... |
1545 1546 |
requeue_futex(this, hb1, hb2, &key2); drop_count++; |
1da177e4c Linux-2.6.12-rc2 |
1547 1548 1549 |
} out_unlock: |
5eb3dc62f futex: add double... |
1550 |
double_unlock_hb(hb1, hb2); |
69cd9eba3 futex: avoid race... |
1551 |
hb_waiters_dec(hb2); |
1da177e4c Linux-2.6.12-rc2 |
1552 |
|
cd84a42f3 futex: comment re... |
1553 1554 1555 1556 1557 1558 |
/* * drop_futex_key_refs() must be called outside the spinlocks. During * the requeue we moved futex_q's from the hash bucket at key1 to the * one at key2 and updated their key pointer. We no longer need to * hold the references to key1. */ |
1da177e4c Linux-2.6.12-rc2 |
1559 |
while (--drop_count >= 0) |
9adef58b1 futex: get_futex_... |
1560 |
drop_futex_key_refs(&key1); |
1da177e4c Linux-2.6.12-rc2 |
1561 |
|
42d35d48c futex: make futex... |
1562 |
out_put_keys: |
ae791a2d2 futex: Cleanup st... |
1563 |
put_futex_key(&key2); |
42d35d48c futex: make futex... |
1564 |
out_put_key1: |
ae791a2d2 futex: Cleanup st... |
1565 |
put_futex_key(&key1); |
42d35d48c futex: make futex... |
1566 |
out: |
52400ba94 futex: add requeu... |
1567 1568 1569 |
if (pi_state != NULL) free_pi_state(pi_state); return ret ? ret : task_count; |
1da177e4c Linux-2.6.12-rc2 |
1570 1571 1572 |
} /* The key must be already stored in q->key. */ |
82af7aca5 Removal of FUTEX_FD |
1573 |
static inline struct futex_hash_bucket *queue_lock(struct futex_q *q) |
15e408cd6 futex: Add lock c... |
1574 |
__acquires(&hb->lock) |
1da177e4c Linux-2.6.12-rc2 |
1575 |
{ |
e2970f2fb [PATCH] pi-futex:... |
1576 |
struct futex_hash_bucket *hb; |
1da177e4c Linux-2.6.12-rc2 |
1577 |
|
e2970f2fb [PATCH] pi-futex:... |
1578 |
hb = hash_futex(&q->key); |
11d4616bd futex: revert bac... |
1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 |
/* * Increment the counter before taking the lock so that * a potential waker won't miss a to-be-slept task that is * waiting for the spinlock. This is safe as all queue_lock() * users end up calling queue_me(). Similarly, for housekeeping, * decrement the counter at queue_unlock() when some error has * occurred and we don't end up adding the task to the list. */ hb_waiters_inc(hb); |
e2970f2fb [PATCH] pi-futex:... |
1589 |
q->lock_ptr = &hb->lock; |
1da177e4c Linux-2.6.12-rc2 |
1590 |
|
b0c29f79e futexes: Avoid ta... |
1591 |
spin_lock(&hb->lock); /* implies MB (A) */ |
e2970f2fb [PATCH] pi-futex:... |
1592 |
return hb; |
1da177e4c Linux-2.6.12-rc2 |
1593 |
} |
d40d65c8d futex: Correct qu... |
1594 |
static inline void |
0d00c7b20 futexes: Clean up... |
1595 |
queue_unlock(struct futex_hash_bucket *hb) |
15e408cd6 futex: Add lock c... |
1596 |
__releases(&hb->lock) |
d40d65c8d futex: Correct qu... |
1597 1598 |
{ spin_unlock(&hb->lock); |
11d4616bd futex: revert bac... |
1599 |
hb_waiters_dec(hb); |
d40d65c8d futex: Correct qu... |
1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 |
} /** * queue_me() - Enqueue the futex_q on the futex_hash_bucket * @q: The futex_q to enqueue * @hb: The destination hash bucket * * The hb->lock must be held by the caller, and is released here. A call to * queue_me() is typically paired with exactly one call to unqueue_me(). The * exceptions involve the PI related operations, which may use unqueue_me_pi() * or nothing if the unqueue is done as part of the wake process and the unqueue * state is implicit in the state of woken task (see futex_wait_requeue_pi() for * an example). */ |
82af7aca5 Removal of FUTEX_FD |
1614 |
static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb) |
15e408cd6 futex: Add lock c... |
1615 |
__releases(&hb->lock) |
1da177e4c Linux-2.6.12-rc2 |
1616 |
{ |
ec92d0829 futex priority ba... |
1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 |
int prio; /* * The priority used to register this element is * - either the real thread-priority for the real-time threads * (i.e. threads with a priority lower than MAX_RT_PRIO) * - or MAX_RT_PRIO for non-RT threads. * Thus, all RT-threads are woken first in priority order, and * the others are woken last, in FIFO order. */ prio = min(current->normal_prio, MAX_RT_PRIO); plist_node_init(&q->list, prio); |
ec92d0829 futex priority ba... |
1630 |
plist_add(&q->list, &hb->chain); |
c87e2837b [PATCH] pi-futex:... |
1631 |
q->task = current; |
e2970f2fb [PATCH] pi-futex:... |
1632 |
spin_unlock(&hb->lock); |
1da177e4c Linux-2.6.12-rc2 |
1633 |
} |
d40d65c8d futex: Correct qu... |
1634 1635 1636 1637 1638 1639 1640 |
/** * unqueue_me() - Remove the futex_q from its futex_hash_bucket * @q: The futex_q to unqueue * * The q->lock_ptr must not be held by the caller. A call to unqueue_me() must * be paired with exactly one earlier call to queue_me(). * |
6c23cbbd5 futex: fix kernel... |
1641 1642 |
* Return: * 1 - if the futex_q was still queued (and we removed unqueued it); |
d40d65c8d futex: Correct qu... |
1643 |
* 0 - if the futex_q was already removed by the waking thread |
1da177e4c Linux-2.6.12-rc2 |
1644 |
*/ |
1da177e4c Linux-2.6.12-rc2 |
1645 1646 |
static int unqueue_me(struct futex_q *q) { |
1da177e4c Linux-2.6.12-rc2 |
1647 |
spinlock_t *lock_ptr; |
e2970f2fb [PATCH] pi-futex:... |
1648 |
int ret = 0; |
1da177e4c Linux-2.6.12-rc2 |
1649 1650 |
/* In the common case we don't take the spinlock, which is nice. */ |
42d35d48c futex: make futex... |
1651 |
retry: |
1da177e4c Linux-2.6.12-rc2 |
1652 |
lock_ptr = q->lock_ptr; |
e91467ecd [PATCH] bug in fu... |
1653 |
barrier(); |
c80544dc0 sparse pointer us... |
1654 |
if (lock_ptr != NULL) { |
1da177e4c Linux-2.6.12-rc2 |
1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 |
spin_lock(lock_ptr); /* * q->lock_ptr can change between reading it and * spin_lock(), causing us to take the wrong lock. This * corrects the race condition. * * Reasoning goes like this: if we have the wrong lock, * q->lock_ptr must have changed (maybe several times) * between reading it and the spin_lock(). It can * change again after the spin_lock() but only if it was * already changed before the spin_lock(). It cannot, * however, change back to the original value. Therefore * we can detect whether we acquired the correct lock. */ if (unlikely(lock_ptr != q->lock_ptr)) { spin_unlock(lock_ptr); goto retry; } |
2e12978a9 futex,plist: Pass... |
1673 |
__unqueue_futex(q); |
c87e2837b [PATCH] pi-futex:... |
1674 1675 |
BUG_ON(q->pi_state); |
1da177e4c Linux-2.6.12-rc2 |
1676 1677 1678 |
spin_unlock(lock_ptr); ret = 1; } |
9adef58b1 futex: get_futex_... |
1679 |
drop_futex_key_refs(&q->key); |
1da177e4c Linux-2.6.12-rc2 |
1680 1681 |
return ret; } |
c87e2837b [PATCH] pi-futex:... |
1682 1683 |
/* * PI futexes can not be requeued and must remove themself from the |
d0aa7a70b futex_requeue_pi ... |
1684 1685 |
* hash bucket. The hash bucket lock (i.e. lock_ptr) is held on entry * and dropped here. |
c87e2837b [PATCH] pi-futex:... |
1686 |
*/ |
d0aa7a70b futex_requeue_pi ... |
1687 |
static void unqueue_me_pi(struct futex_q *q) |
15e408cd6 futex: Add lock c... |
1688 |
__releases(q->lock_ptr) |
c87e2837b [PATCH] pi-futex:... |
1689 |
{ |
2e12978a9 futex,plist: Pass... |
1690 |
__unqueue_futex(q); |
c87e2837b [PATCH] pi-futex:... |
1691 1692 1693 1694 |
BUG_ON(!q->pi_state); free_pi_state(q->pi_state); q->pi_state = NULL; |
d0aa7a70b futex_requeue_pi ... |
1695 |
spin_unlock(q->lock_ptr); |
c87e2837b [PATCH] pi-futex:... |
1696 |
} |
d0aa7a70b futex_requeue_pi ... |
1697 |
/* |
cdf71a10c futex: Prevent st... |
1698 |
* Fixup the pi_state owner with the new owner. |
d0aa7a70b futex_requeue_pi ... |
1699 |
* |
778e9a9c3 pi-futex: fix exi... |
1700 1701 |
* Must be called with hash bucket lock held and mm->sem held for non * private futexes. |
d0aa7a70b futex_requeue_pi ... |
1702 |
*/ |
778e9a9c3 pi-futex: fix exi... |
1703 |
static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q, |
ae791a2d2 futex: Cleanup st... |
1704 |
struct task_struct *newowner) |
d0aa7a70b futex_requeue_pi ... |
1705 |
{ |
cdf71a10c futex: Prevent st... |
1706 |
u32 newtid = task_pid_vnr(newowner) | FUTEX_WAITERS; |
d0aa7a70b futex_requeue_pi ... |
1707 |
struct futex_pi_state *pi_state = q->pi_state; |
1b7558e45 futexes: fix faul... |
1708 |
struct task_struct *oldowner = pi_state->owner; |
7cfdaf38d futex: uninitiali... |
1709 |
u32 uval, uninitialized_var(curval), newval; |
e4dc5b7a3 futex: clean up f... |
1710 |
int ret; |
d0aa7a70b futex_requeue_pi ... |
1711 1712 |
/* Owner died? */ |
1b7558e45 futexes: fix faul... |
1713 1714 1715 1716 1717 |
if (!pi_state->owner) newtid |= FUTEX_OWNER_DIED; /* * We are here either because we stole the rtmutex from the |
8161239a8 rtmutex: Simplify... |
1718 1719 1720 1721 |
* previous highest priority waiter or we are the highest priority * waiter but failed to get the rtmutex the first time. * We have to replace the newowner TID in the user space variable. * This must be atomic as we have to preserve the owner died bit here. |
1b7558e45 futexes: fix faul... |
1722 |
* |
b2d0994b1 futex: update fut... |
1723 1724 1725 |
* Note: We write the user space value _before_ changing the pi_state * because we can fault here. Imagine swapped out pages or a fork * that marked all the anonymous memory readonly for cow. |
1b7558e45 futexes: fix faul... |
1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 |
* * Modifying pi_state _before_ the user space value would * leave the pi_state in an inconsistent state when we fault * here, because we need to drop the hash bucket lock to * handle the fault. This might be observed in the PID check * in lookup_pi_state. */ retry: if (get_futex_value_locked(&uval, uaddr)) goto handle_fault; while (1) { newval = (uval & FUTEX_OWNER_DIED) | newtid; |
37a9d912b futex: Sanitize c... |
1739 |
if (cmpxchg_futex_value_locked(&curval, uaddr, uval, newval)) |
1b7558e45 futexes: fix faul... |
1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 |
goto handle_fault; if (curval == uval) break; uval = curval; } /* * We fixed up user space. Now we need to fix the pi_state * itself. */ |
d0aa7a70b futex_requeue_pi ... |
1750 |
if (pi_state->owner != NULL) { |
1d6154825 sched: Convert pi... |
1751 |
raw_spin_lock_irq(&pi_state->owner->pi_lock); |
d0aa7a70b futex_requeue_pi ... |
1752 1753 |
WARN_ON(list_empty(&pi_state->list)); list_del_init(&pi_state->list); |
1d6154825 sched: Convert pi... |
1754 |
raw_spin_unlock_irq(&pi_state->owner->pi_lock); |
1b7558e45 futexes: fix faul... |
1755 |
} |
d0aa7a70b futex_requeue_pi ... |
1756 |
|
cdf71a10c futex: Prevent st... |
1757 |
pi_state->owner = newowner; |
d0aa7a70b futex_requeue_pi ... |
1758 |
|
1d6154825 sched: Convert pi... |
1759 |
raw_spin_lock_irq(&newowner->pi_lock); |
d0aa7a70b futex_requeue_pi ... |
1760 |
WARN_ON(!list_empty(&pi_state->list)); |
cdf71a10c futex: Prevent st... |
1761 |
list_add(&pi_state->list, &newowner->pi_state_list); |
1d6154825 sched: Convert pi... |
1762 |
raw_spin_unlock_irq(&newowner->pi_lock); |
1b7558e45 futexes: fix faul... |
1763 |
return 0; |
d0aa7a70b futex_requeue_pi ... |
1764 |
|
d0aa7a70b futex_requeue_pi ... |
1765 |
/* |
1b7558e45 futexes: fix faul... |
1766 |
* To handle the page fault we need to drop the hash bucket |
8161239a8 rtmutex: Simplify... |
1767 1768 |
* lock here. That gives the other task (either the highest priority * waiter itself or the task which stole the rtmutex) the |
1b7558e45 futexes: fix faul... |
1769 1770 1771 1772 1773 |
* chance to try the fixup of the pi_state. So once we are * back from handling the fault we need to check the pi_state * after reacquiring the hash bucket lock and before trying to * do another fixup. When the fixup has been done already we * simply return. |
d0aa7a70b futex_requeue_pi ... |
1774 |
*/ |
1b7558e45 futexes: fix faul... |
1775 1776 |
handle_fault: spin_unlock(q->lock_ptr); |
778e9a9c3 pi-futex: fix exi... |
1777 |
|
d0725992c futex: Fix the wr... |
1778 |
ret = fault_in_user_writeable(uaddr); |
778e9a9c3 pi-futex: fix exi... |
1779 |
|
1b7558e45 futexes: fix faul... |
1780 |
spin_lock(q->lock_ptr); |
778e9a9c3 pi-futex: fix exi... |
1781 |
|
1b7558e45 futexes: fix faul... |
1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 |
/* * Check if someone else fixed it for us: */ if (pi_state->owner != oldowner) return 0; if (ret) return ret; goto retry; |
d0aa7a70b futex_requeue_pi ... |
1792 |
} |
72c1bbf30 futex: restartabl... |
1793 |
static long futex_wait_restart(struct restart_block *restart); |
36cf3b5c3 FUTEX: Tidy up th... |
1794 |
|
ca5f9524d futex: separate f... |
1795 |
/** |
dd9739980 futex: split out ... |
1796 1797 |
* fixup_owner() - Post lock pi_state and corner case management * @uaddr: user address of the futex |
dd9739980 futex: split out ... |
1798 1799 1800 1801 1802 1803 1804 |
* @q: futex_q (contains pi_state and access to the rt_mutex) * @locked: if the attempt to take the rt_mutex succeeded (1) or not (0) * * After attempting to lock an rt_mutex, this function is called to cleanup * the pi_state owner as well as handle race conditions that may allow us to * acquire the lock. Must be called with the hb lock held. * |
6c23cbbd5 futex: fix kernel... |
1805 1806 1807 |
* Return: * 1 - success, lock taken; * 0 - success, lock not taken; |
dd9739980 futex: split out ... |
1808 1809 |
* <0 - on error (-EFAULT) */ |
ae791a2d2 futex: Cleanup st... |
1810 |
static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked) |
dd9739980 futex: split out ... |
1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 |
{ struct task_struct *owner; int ret = 0; if (locked) { /* * Got the lock. We might not be the anticipated owner if we * did a lock-steal - fix up the PI-state in that case: */ if (q->pi_state->owner != current) |
ae791a2d2 futex: Cleanup st... |
1821 |
ret = fixup_pi_state_owner(uaddr, q, current); |
dd9739980 futex: split out ... |
1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 |
goto out; } /* * Catch the rare case, where the lock was released when we were on the * way back before we locked the hash bucket. */ if (q->pi_state->owner == current) { /* * Try to get the rt_mutex now. This might fail as some other * task acquired the rt_mutex after we removed ourself from the * rt_mutex waiters list. */ if (rt_mutex_trylock(&q->pi_state->pi_mutex)) { locked = 1; goto out; } /* * pi_state is incorrect, some other task did a lock steal and * we returned due to timeout or signal without taking the |
8161239a8 rtmutex: Simplify... |
1843 |
* rt_mutex. Too late. |
dd9739980 futex: split out ... |
1844 |
*/ |
8161239a8 rtmutex: Simplify... |
1845 |
raw_spin_lock(&q->pi_state->pi_mutex.wait_lock); |
dd9739980 futex: split out ... |
1846 |
owner = rt_mutex_owner(&q->pi_state->pi_mutex); |
8161239a8 rtmutex: Simplify... |
1847 1848 1849 |
if (!owner) owner = rt_mutex_next_owner(&q->pi_state->pi_mutex); raw_spin_unlock(&q->pi_state->pi_mutex.wait_lock); |
ae791a2d2 futex: Cleanup st... |
1850 |
ret = fixup_pi_state_owner(uaddr, q, owner); |
dd9739980 futex: split out ... |
1851 1852 1853 1854 1855 |
goto out; } /* * Paranoia check. If we did not take the lock, then we should not be |
8161239a8 rtmutex: Simplify... |
1856 |
* the owner of the rt_mutex. |
dd9739980 futex: split out ... |
1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 |
*/ if (rt_mutex_owner(&q->pi_state->pi_mutex) == current) printk(KERN_ERR "fixup_owner: ret = %d pi-mutex: %p " "pi-state %p ", ret, q->pi_state->pi_mutex.owner, q->pi_state->owner); out: return ret ? ret : locked; } /** |
ca5f9524d futex: separate f... |
1870 1871 1872 1873 |
* futex_wait_queue_me() - queue_me() and wait for wakeup, timeout, or signal * @hb: the futex hash bucket, must be locked by the caller * @q: the futex_q to queue up on * @timeout: the prepared hrtimer_sleeper, or null for no timeout |
ca5f9524d futex: separate f... |
1874 1875 |
*/ static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q, |
f1a11e057 futex: remove the... |
1876 |
struct hrtimer_sleeper *timeout) |
ca5f9524d futex: separate f... |
1877 |
{ |
9beba3c54 futex: Add memory... |
1878 1879 1880 1881 1882 1883 |
/* * The task state is guaranteed to be set before another task can * wake it. set_current_state() is implemented using set_mb() and * queue_me() calls spin_unlock() upon completion, both serializing * access to the hash list and forcing another memory barrier. */ |
f1a11e057 futex: remove the... |
1884 |
set_current_state(TASK_INTERRUPTIBLE); |
0729e1961 futex: Fix wakeup... |
1885 |
queue_me(q, hb); |
ca5f9524d futex: separate f... |
1886 1887 1888 1889 1890 1891 1892 1893 1894 |
/* Arm the timer */ if (timeout) { hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS); if (!hrtimer_active(&timeout->timer)) timeout->task = NULL; } /* |
0729e1961 futex: Fix wakeup... |
1895 1896 |
* If we have been removed from the hash list, then another task * has tried to wake us, and we can skip the call to schedule(). |
ca5f9524d futex: separate f... |
1897 1898 1899 1900 1901 1902 1903 1904 |
*/ if (likely(!plist_node_empty(&q->list))) { /* * If the timer has already expired, current will already be * flagged for rescheduling. Only call schedule if there * is no timeout, or if it has yet to expire. */ if (!timeout || timeout->task) |
88c8004fd futex: Use freeza... |
1905 |
freezable_schedule(); |
ca5f9524d futex: separate f... |
1906 1907 1908 |
} __set_current_state(TASK_RUNNING); } |
f801073f8 futex: split out ... |
1909 1910 1911 1912 |
/** * futex_wait_setup() - Prepare to wait on a futex * @uaddr: the futex userspace address * @val: the expected value |
b41277dc7 futex: Replace fs... |
1913 |
* @flags: futex flags (FLAGS_SHARED, etc.) |
f801073f8 futex: split out ... |
1914 1915 1916 1917 1918 1919 1920 1921 |
* @q: the associated futex_q * @hb: storage for hash_bucket pointer to be returned to caller * * Setup the futex_q and locate the hash_bucket. Get the futex value and * compare it with the expected value. Handle atomic faults internally. * Return with the hb lock held and a q.key reference on success, and unlocked * with no q.key reference on failure. * |
6c23cbbd5 futex: fix kernel... |
1922 1923 |
* Return: * 0 - uaddr contains val and hb has been locked; |
ca4a04cf3 futex: Fix spelli... |
1924 |
* <1 - -EFAULT or -EWOULDBLOCK (uaddr does not contain val) and hb is unlocked |
f801073f8 futex: split out ... |
1925 |
*/ |
b41277dc7 futex: Replace fs... |
1926 |
static int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags, |
f801073f8 futex: split out ... |
1927 |
struct futex_q *q, struct futex_hash_bucket **hb) |
1da177e4c Linux-2.6.12-rc2 |
1928 |
{ |
e2970f2fb [PATCH] pi-futex:... |
1929 1930 |
u32 uval; int ret; |
1da177e4c Linux-2.6.12-rc2 |
1931 |
|
1da177e4c Linux-2.6.12-rc2 |
1932 |
/* |
b2d0994b1 futex: update fut... |
1933 |
* Access the page AFTER the hash-bucket is locked. |
1da177e4c Linux-2.6.12-rc2 |
1934 1935 1936 1937 1938 1939 1940 |
* Order is important: * * Userspace waiter: val = var; if (cond(val)) futex_wait(&var, val); * Userspace waker: if (cond(var)) { var = new; futex_wake(&var); } * * The basic logical guarantee of a futex is that it blocks ONLY * if cond(var) is known to be true at the time of blocking, for |
8fe8f545c futex: Update fut... |
1941 1942 |
* any cond. If we locked the hash-bucket after testing *uaddr, that * would open a race condition where we could block indefinitely with |
1da177e4c Linux-2.6.12-rc2 |
1943 1944 |
* cond(var) false, which would violate the guarantee. * |
8fe8f545c futex: Update fut... |
1945 1946 1947 1948 |
* On the other hand, we insert q and release the hash-bucket only * after testing *uaddr. This guarantees that futex_wait() will NOT * absorb a wakeup if *uaddr does not match the desired values * while the syscall executes. |
1da177e4c Linux-2.6.12-rc2 |
1949 |
*/ |
f801073f8 futex: split out ... |
1950 |
retry: |
9ea71503a futex: Fix regres... |
1951 |
ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key, VERIFY_READ); |
f801073f8 futex: split out ... |
1952 |
if (unlikely(ret != 0)) |
a5a2a0c7f futex: fix futex_... |
1953 |
return ret; |
f801073f8 futex: split out ... |
1954 1955 1956 |
retry_private: *hb = queue_lock(q); |
e2970f2fb [PATCH] pi-futex:... |
1957 |
ret = get_futex_value_locked(&uval, uaddr); |
1da177e4c Linux-2.6.12-rc2 |
1958 |
|
f801073f8 futex: split out ... |
1959 |
if (ret) { |
0d00c7b20 futexes: Clean up... |
1960 |
queue_unlock(*hb); |
1da177e4c Linux-2.6.12-rc2 |
1961 |
|
e2970f2fb [PATCH] pi-futex:... |
1962 |
ret = get_user(uval, uaddr); |
e4dc5b7a3 futex: clean up f... |
1963 |
if (ret) |
f801073f8 futex: split out ... |
1964 |
goto out; |
1da177e4c Linux-2.6.12-rc2 |
1965 |
|
b41277dc7 futex: Replace fs... |
1966 |
if (!(flags & FLAGS_SHARED)) |
e4dc5b7a3 futex: clean up f... |
1967 |
goto retry_private; |
ae791a2d2 futex: Cleanup st... |
1968 |
put_futex_key(&q->key); |
e4dc5b7a3 futex: clean up f... |
1969 |
goto retry; |
1da177e4c Linux-2.6.12-rc2 |
1970 |
} |
ca5f9524d futex: separate f... |
1971 |
|
f801073f8 futex: split out ... |
1972 |
if (uval != val) { |
0d00c7b20 futexes: Clean up... |
1973 |
queue_unlock(*hb); |
f801073f8 futex: split out ... |
1974 |
ret = -EWOULDBLOCK; |
2fff78c78 futex: fix refere... |
1975 |
} |
1da177e4c Linux-2.6.12-rc2 |
1976 |
|
f801073f8 futex: split out ... |
1977 1978 |
out: if (ret) |
ae791a2d2 futex: Cleanup st... |
1979 |
put_futex_key(&q->key); |
f801073f8 futex: split out ... |
1980 1981 |
return ret; } |
b41277dc7 futex: Replace fs... |
1982 1983 |
static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, ktime_t *abs_time, u32 bitset) |
f801073f8 futex: split out ... |
1984 1985 |
{ struct hrtimer_sleeper timeout, *to = NULL; |
f801073f8 futex: split out ... |
1986 1987 |
struct restart_block *restart; struct futex_hash_bucket *hb; |
5bdb05f91 futex: Add futex_... |
1988 |
struct futex_q q = futex_q_init; |
f801073f8 futex: split out ... |
1989 1990 1991 1992 |
int ret; if (!bitset) return -EINVAL; |
f801073f8 futex: split out ... |
1993 1994 1995 1996 |
q.bitset = bitset; if (abs_time) { to = &timeout; |
b41277dc7 futex: Replace fs... |
1997 1998 1999 |
hrtimer_init_on_stack(&to->timer, (flags & FLAGS_CLOCKRT) ? CLOCK_REALTIME : CLOCK_MONOTONIC, HRTIMER_MODE_ABS); |
f801073f8 futex: split out ... |
2000 2001 2002 2003 |
hrtimer_init_sleeper(to, current); hrtimer_set_expires_range_ns(&to->timer, *abs_time, current->timer_slack_ns); } |
d58e6576b futex: Handle spu... |
2004 |
retry: |
7ada876a8 futex: Fix errors... |
2005 2006 2007 2008 |
/* * Prepare to wait on uaddr. On success, holds hb lock and increments * q.key refs. */ |
b41277dc7 futex: Replace fs... |
2009 |
ret = futex_wait_setup(uaddr, val, flags, &q, &hb); |
f801073f8 futex: split out ... |
2010 2011 |
if (ret) goto out; |
ca5f9524d futex: separate f... |
2012 |
/* queue_me and wait for wakeup, timeout, or a signal. */ |
f1a11e057 futex: remove the... |
2013 |
futex_wait_queue_me(hb, &q, to); |
1da177e4c Linux-2.6.12-rc2 |
2014 2015 |
/* If we were woken (and unqueued), we succeeded, whatever. */ |
2fff78c78 futex: fix refere... |
2016 |
ret = 0; |
7ada876a8 futex: Fix errors... |
2017 |
/* unqueue_me() drops q.key ref */ |
1da177e4c Linux-2.6.12-rc2 |
2018 |
if (!unqueue_me(&q)) |
7ada876a8 futex: Fix errors... |
2019 |
goto out; |
2fff78c78 futex: fix refere... |
2020 |
ret = -ETIMEDOUT; |
ca5f9524d futex: separate f... |
2021 |
if (to && !to->task) |
7ada876a8 futex: Fix errors... |
2022 |
goto out; |
72c1bbf30 futex: restartabl... |
2023 |
|
e2970f2fb [PATCH] pi-futex:... |
2024 |
/* |
d58e6576b futex: Handle spu... |
2025 2026 |
* We expect signal_pending(current), but we might be the * victim of a spurious wakeup as well. |
e2970f2fb [PATCH] pi-futex:... |
2027 |
*/ |
7ada876a8 futex: Fix errors... |
2028 |
if (!signal_pending(current)) |
d58e6576b futex: Handle spu... |
2029 |
goto retry; |
d58e6576b futex: Handle spu... |
2030 |
|
2fff78c78 futex: fix refere... |
2031 |
ret = -ERESTARTSYS; |
c19384b5b Make futex_wait()... |
2032 |
if (!abs_time) |
7ada876a8 futex: Fix errors... |
2033 |
goto out; |
1da177e4c Linux-2.6.12-rc2 |
2034 |
|
2fff78c78 futex: fix refere... |
2035 2036 |
restart = ¤t_thread_info()->restart_block; restart->fn = futex_wait_restart; |
a3c74c525 futex: Mark resta... |
2037 |
restart->futex.uaddr = uaddr; |
2fff78c78 futex: fix refere... |
2038 2039 2040 |
restart->futex.val = val; restart->futex.time = abs_time->tv64; restart->futex.bitset = bitset; |
0cd9c6494 futex: Set FLAGS_... |
2041 |
restart->futex.flags = flags | FLAGS_HAS_TIMEOUT; |
42d35d48c futex: make futex... |
2042 |
|
2fff78c78 futex: fix refere... |
2043 |
ret = -ERESTART_RESTARTBLOCK; |
42d35d48c futex: make futex... |
2044 |
out: |
ca5f9524d futex: separate f... |
2045 2046 2047 2048 |
if (to) { hrtimer_cancel(&to->timer); destroy_hrtimer_on_stack(&to->timer); } |
c87e2837b [PATCH] pi-futex:... |
2049 2050 |
return ret; } |
72c1bbf30 futex: restartabl... |
2051 2052 2053 |
static long futex_wait_restart(struct restart_block *restart) { |
a3c74c525 futex: Mark resta... |
2054 |
u32 __user *uaddr = restart->futex.uaddr; |
a72188d8a futex: add FUTEX_... |
2055 |
ktime_t t, *tp = NULL; |
72c1bbf30 futex: restartabl... |
2056 |
|
a72188d8a futex: add FUTEX_... |
2057 2058 2059 2060 |
if (restart->futex.flags & FLAGS_HAS_TIMEOUT) { t.tv64 = restart->futex.time; tp = &t; } |
72c1bbf30 futex: restartabl... |
2061 |
restart->fn = do_no_restart_syscall; |
b41277dc7 futex: Replace fs... |
2062 2063 2064 |
return (long)futex_wait(uaddr, restart->futex.flags, restart->futex.val, tp, restart->futex.bitset); |
72c1bbf30 futex: restartabl... |
2065 |
} |
c87e2837b [PATCH] pi-futex:... |
2066 2067 2068 2069 2070 2071 |
/* * Userspace tried a 0 -> TID atomic transition of the futex value * and failed. The kernel side here does the whole locking operation: * if there are waiters then it will block, it does PI, etc. (Due to * races the kernel might see a 0 value of the futex too.) */ |
b41277dc7 futex: Replace fs... |
2072 2073 |
static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, int detect, ktime_t *time, int trylock) |
c87e2837b [PATCH] pi-futex:... |
2074 |
{ |
c5780e976 [PATCH] Use the c... |
2075 |
struct hrtimer_sleeper timeout, *to = NULL; |
c87e2837b [PATCH] pi-futex:... |
2076 |
struct futex_hash_bucket *hb; |
5bdb05f91 futex: Add futex_... |
2077 |
struct futex_q q = futex_q_init; |
dd9739980 futex: split out ... |
2078 |
int res, ret; |
c87e2837b [PATCH] pi-futex:... |
2079 2080 2081 |
if (refill_pi_state_cache()) return -ENOMEM; |
c19384b5b Make futex_wait()... |
2082 |
if (time) { |
c5780e976 [PATCH] Use the c... |
2083 |
to = &timeout; |
237fc6e7a add hrtimer speci... |
2084 2085 |
hrtimer_init_on_stack(&to->timer, CLOCK_REALTIME, HRTIMER_MODE_ABS); |
c5780e976 [PATCH] Use the c... |
2086 |
hrtimer_init_sleeper(to, current); |
cc584b213 hrtimer: convert ... |
2087 |
hrtimer_set_expires(&to->timer, *time); |
c5780e976 [PATCH] Use the c... |
2088 |
} |
42d35d48c futex: make futex... |
2089 |
retry: |
9ea71503a futex: Fix regres... |
2090 |
ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, VERIFY_WRITE); |
c87e2837b [PATCH] pi-futex:... |
2091 |
if (unlikely(ret != 0)) |
42d35d48c futex: make futex... |
2092 |
goto out; |
c87e2837b [PATCH] pi-futex:... |
2093 |
|
e4dc5b7a3 futex: clean up f... |
2094 |
retry_private: |
82af7aca5 Removal of FUTEX_FD |
2095 |
hb = queue_lock(&q); |
c87e2837b [PATCH] pi-futex:... |
2096 |
|
bab5bc9e8 futex: fixup unlo... |
2097 |
ret = futex_lock_pi_atomic(uaddr, hb, &q.key, &q.pi_state, current, 0); |
c87e2837b [PATCH] pi-futex:... |
2098 |
if (unlikely(ret)) { |
778e9a9c3 pi-futex: fix exi... |
2099 |
switch (ret) { |
1a52084d0 futex: split out ... |
2100 2101 2102 2103 2104 2105 |
case 1: /* We got the lock. */ ret = 0; goto out_unlock_put_key; case -EFAULT: goto uaddr_faulted; |
778e9a9c3 pi-futex: fix exi... |
2106 2107 2108 2109 2110 |
case -EAGAIN: /* * Task is exiting and we just wait for the * exit to complete. */ |
0d00c7b20 futexes: Clean up... |
2111 |
queue_unlock(hb); |
ae791a2d2 futex: Cleanup st... |
2112 |
put_futex_key(&q.key); |
778e9a9c3 pi-futex: fix exi... |
2113 2114 |
cond_resched(); goto retry; |
778e9a9c3 pi-futex: fix exi... |
2115 |
default: |
42d35d48c futex: make futex... |
2116 |
goto out_unlock_put_key; |
c87e2837b [PATCH] pi-futex:... |
2117 |
} |
c87e2837b [PATCH] pi-futex:... |
2118 2119 2120 2121 2122 |
} /* * Only actually queue now that the atomic ops are done: */ |
82af7aca5 Removal of FUTEX_FD |
2123 |
queue_me(&q, hb); |
c87e2837b [PATCH] pi-futex:... |
2124 |
|
c87e2837b [PATCH] pi-futex:... |
2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 |
WARN_ON(!q.pi_state); /* * Block on the PI mutex: */ if (!trylock) ret = rt_mutex_timed_lock(&q.pi_state->pi_mutex, to, 1); else { ret = rt_mutex_trylock(&q.pi_state->pi_mutex); /* Fixup the trylock return value: */ ret = ret ? 0 : -EWOULDBLOCK; } |
a99e4e413 [PATCH] pi-futex:... |
2136 |
spin_lock(q.lock_ptr); |
dd9739980 futex: split out ... |
2137 2138 2139 2140 |
/* * Fixup the pi_state owner and possibly acquire the lock if we * haven't already. */ |
ae791a2d2 futex: Cleanup st... |
2141 |
res = fixup_owner(uaddr, &q, !ret); |
dd9739980 futex: split out ... |
2142 2143 2144 2145 2146 2147 |
/* * If fixup_owner() returned an error, proprogate that. If it acquired * the lock, clear our -ETIMEDOUT or -EINTR. */ if (res) ret = (res < 0) ? res : 0; |
c87e2837b [PATCH] pi-futex:... |
2148 |
|
e8f6386c0 futex: unlock bef... |
2149 |
/* |
dd9739980 futex: split out ... |
2150 2151 |
* If fixup_owner() faulted and was unable to handle the fault, unlock * it and return the fault to userspace. |
e8f6386c0 futex: unlock bef... |
2152 2153 2154 |
*/ if (ret && (rt_mutex_owner(&q.pi_state->pi_mutex) == current)) rt_mutex_unlock(&q.pi_state->pi_mutex); |
778e9a9c3 pi-futex: fix exi... |
2155 2156 |
/* Unqueue and drop the lock */ unqueue_me_pi(&q); |
c87e2837b [PATCH] pi-futex:... |
2157 |
|
5ecb01cfd futex_lock_pi() k... |
2158 |
goto out_put_key; |
c87e2837b [PATCH] pi-futex:... |
2159 |
|
42d35d48c futex: make futex... |
2160 |
out_unlock_put_key: |
0d00c7b20 futexes: Clean up... |
2161 |
queue_unlock(hb); |
c87e2837b [PATCH] pi-futex:... |
2162 |
|
42d35d48c futex: make futex... |
2163 |
out_put_key: |
ae791a2d2 futex: Cleanup st... |
2164 |
put_futex_key(&q.key); |
42d35d48c futex: make futex... |
2165 |
out: |
237fc6e7a add hrtimer speci... |
2166 2167 |
if (to) destroy_hrtimer_on_stack(&to->timer); |
dd9739980 futex: split out ... |
2168 |
return ret != -EINTR ? ret : -ERESTARTNOINTR; |
c87e2837b [PATCH] pi-futex:... |
2169 |
|
42d35d48c futex: make futex... |
2170 |
uaddr_faulted: |
0d00c7b20 futexes: Clean up... |
2171 |
queue_unlock(hb); |
778e9a9c3 pi-futex: fix exi... |
2172 |
|
d0725992c futex: Fix the wr... |
2173 |
ret = fault_in_user_writeable(uaddr); |
e4dc5b7a3 futex: clean up f... |
2174 2175 |
if (ret) goto out_put_key; |
c87e2837b [PATCH] pi-futex:... |
2176 |
|
b41277dc7 futex: Replace fs... |
2177 |
if (!(flags & FLAGS_SHARED)) |
e4dc5b7a3 futex: clean up f... |
2178 |
goto retry_private; |
ae791a2d2 futex: Cleanup st... |
2179 |
put_futex_key(&q.key); |
e4dc5b7a3 futex: clean up f... |
2180 |
goto retry; |
c87e2837b [PATCH] pi-futex:... |
2181 2182 2183 |
} /* |
c87e2837b [PATCH] pi-futex:... |
2184 2185 2186 2187 |
* Userspace attempted a TID -> 0 atomic transition, and failed. * This is the in-kernel slowpath: we look up the PI state (if any), * and do the rt-mutex unlock. */ |
b41277dc7 futex: Replace fs... |
2188 |
static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags) |
c87e2837b [PATCH] pi-futex:... |
2189 2190 2191 |
{ struct futex_hash_bucket *hb; struct futex_q *this, *next; |
38d47c1b7 futex: rely on ge... |
2192 |
union futex_key key = FUTEX_KEY_INIT; |
c0c9ed150 futex: Avoid redu... |
2193 |
u32 uval, vpid = task_pid_vnr(current); |
e4dc5b7a3 futex: clean up f... |
2194 |
int ret; |
c87e2837b [PATCH] pi-futex:... |
2195 2196 2197 2198 2199 2200 2201 |
retry: if (get_user(uval, uaddr)) return -EFAULT; /* * We release only a lock we actually own: */ |
c0c9ed150 futex: Avoid redu... |
2202 |
if ((uval & FUTEX_TID_MASK) != vpid) |
c87e2837b [PATCH] pi-futex:... |
2203 |
return -EPERM; |
c87e2837b [PATCH] pi-futex:... |
2204 |
|
9ea71503a futex: Fix regres... |
2205 |
ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, VERIFY_WRITE); |
c87e2837b [PATCH] pi-futex:... |
2206 2207 2208 2209 2210 |
if (unlikely(ret != 0)) goto out; hb = hash_futex(&key); spin_lock(&hb->lock); |
c87e2837b [PATCH] pi-futex:... |
2211 2212 2213 2214 2215 |
/* * To avoid races, try to do the TID -> 0 atomic transition * again. If it succeeds then we can return without waking * anyone else up: */ |
37a9d912b futex: Sanitize c... |
2216 2217 |
if (!(uval & FUTEX_OWNER_DIED) && cmpxchg_futex_value_locked(&uval, uaddr, vpid, 0)) |
c87e2837b [PATCH] pi-futex:... |
2218 2219 2220 2221 2222 |
goto pi_faulted; /* * Rare case: we managed to release the lock atomically, * no need to wake anyone else up: */ |
c0c9ed150 futex: Avoid redu... |
2223 |
if (unlikely(uval == vpid)) |
c87e2837b [PATCH] pi-futex:... |
2224 2225 2226 2227 2228 2229 |
goto out_unlock; /* * Ok, other tasks may need to be woken up - check waiters * and do the wakeup if necessary: */ |
0d00c7b20 futexes: Clean up... |
2230 |
plist_for_each_entry_safe(this, next, &hb->chain, list) { |
c87e2837b [PATCH] pi-futex:... |
2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 |
if (!match_futex (&this->key, &key)) continue; ret = wake_futex_pi(uaddr, uval, this); /* * The atomic access to the futex value * generated a pagefault, so retry the * user-access and the wakeup: */ if (ret == -EFAULT) goto pi_faulted; goto out_unlock; } /* * No waiters - kernel unlocks the futex: */ |
e3f2ddeac [PATCH] pi-futex:... |
2246 2247 2248 2249 2250 |
if (!(uval & FUTEX_OWNER_DIED)) { ret = unlock_futex_pi(uaddr, uval); if (ret == -EFAULT) goto pi_faulted; } |
c87e2837b [PATCH] pi-futex:... |
2251 2252 2253 |
out_unlock: spin_unlock(&hb->lock); |
ae791a2d2 futex: Cleanup st... |
2254 |
put_futex_key(&key); |
c87e2837b [PATCH] pi-futex:... |
2255 |
|
42d35d48c futex: make futex... |
2256 |
out: |
c87e2837b [PATCH] pi-futex:... |
2257 2258 2259 |
return ret; pi_faulted: |
778e9a9c3 pi-futex: fix exi... |
2260 |
spin_unlock(&hb->lock); |
ae791a2d2 futex: Cleanup st... |
2261 |
put_futex_key(&key); |
c87e2837b [PATCH] pi-futex:... |
2262 |
|
d0725992c futex: Fix the wr... |
2263 |
ret = fault_in_user_writeable(uaddr); |
b56863630 futex: clean up f... |
2264 |
if (!ret) |
c87e2837b [PATCH] pi-futex:... |
2265 |
goto retry; |
1da177e4c Linux-2.6.12-rc2 |
2266 2267 |
return ret; } |
52400ba94 futex: add requeu... |
2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 |
/** * handle_early_requeue_pi_wakeup() - Detect early wakeup on the initial futex * @hb: the hash_bucket futex_q was original enqueued on * @q: the futex_q woken while waiting to be requeued * @key2: the futex_key of the requeue target futex * @timeout: the timeout associated with the wait (NULL if none) * * Detect if the task was woken on the initial futex as opposed to the requeue * target futex. If so, determine if it was a timeout or a signal that caused * the wakeup and return the appropriate error code to the caller. Must be * called with the hb lock held. * |
6c23cbbd5 futex: fix kernel... |
2280 2281 2282 |
* Return: * 0 = no early wakeup detected; * <0 = -ETIMEDOUT or -ERESTARTNOINTR |
52400ba94 futex: add requeu... |
2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 |
*/ static inline int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb, struct futex_q *q, union futex_key *key2, struct hrtimer_sleeper *timeout) { int ret = 0; /* * With the hb lock held, we avoid races while we process the wakeup. * We only need to hold hb (and not hb2) to ensure atomicity as the * wakeup code can't change q.key from uaddr to uaddr2 if we hold hb. * It can't be requeued from uaddr2 to something else since we don't * support a PI aware source futex for requeue. */ if (!match_futex(&q->key, key2)) { WARN_ON(q->lock_ptr && (&hb->lock != q->lock_ptr)); /* * We were woken prior to requeue by a timeout or a signal. * Unqueue the futex_q and determine which it was. */ |
2e12978a9 futex,plist: Pass... |
2304 |
plist_del(&q->list, &hb->chain); |
11d4616bd futex: revert bac... |
2305 |
hb_waiters_dec(hb); |
52400ba94 futex: add requeu... |
2306 |
|
d58e6576b futex: Handle spu... |
2307 |
/* Handle spurious wakeups gracefully */ |
11df6dddc futex: Fix spurio... |
2308 |
ret = -EWOULDBLOCK; |
52400ba94 futex: add requeu... |
2309 2310 |
if (timeout && !timeout->task) ret = -ETIMEDOUT; |
d58e6576b futex: Handle spu... |
2311 |
else if (signal_pending(current)) |
1c840c149 futex: fix restar... |
2312 |
ret = -ERESTARTNOINTR; |
52400ba94 futex: add requeu... |
2313 2314 2315 2316 2317 2318 |
} return ret; } /** * futex_wait_requeue_pi() - Wait on uaddr and take uaddr2 |
56ec1607b futex: Correct fu... |
2319 |
* @uaddr: the futex we initially wait on (non-pi) |
b41277dc7 futex: Replace fs... |
2320 |
* @flags: futex flags (FLAGS_SHARED, FLAGS_CLOCKRT, etc.), they must be |
52400ba94 futex: add requeu... |
2321 2322 2323 |
* the same type, no requeueing from private to shared, etc. * @val: the expected value of uaddr * @abs_time: absolute timeout |
56ec1607b futex: Correct fu... |
2324 |
* @bitset: 32 bit wakeup bitset set by userspace, defaults to all |
52400ba94 futex: add requeu... |
2325 2326 2327 |
* @uaddr2: the pi futex we will take prior to returning to user-space * * The caller will wait on uaddr and will be requeued by futex_requeue() to |
6f7b0a2a5 futex: Forbid uad... |
2328 2329 2330 2331 2332 |
* uaddr2 which must be PI aware and unique from uaddr. Normal wakeup will wake * on uaddr2 and complete the acquisition of the rt_mutex prior to returning to * userspace. This ensures the rt_mutex maintains an owner when it has waiters; * without one, the pi logic would not know which task to boost/deboost, if * there was a need to. |
52400ba94 futex: add requeu... |
2333 2334 |
* * We call schedule in futex_wait_queue_me() when we enqueue and return there |
6c23cbbd5 futex: fix kernel... |
2335 |
* via the following-- |
52400ba94 futex: add requeu... |
2336 |
* 1) wakeup on uaddr2 after an atomic lock acquisition by futex_requeue() |
cc6db4e60 futex: Correct fu... |
2337 2338 2339 |
* 2) wakeup on uaddr2 after a requeue * 3) signal * 4) timeout |
52400ba94 futex: add requeu... |
2340 |
* |
cc6db4e60 futex: Correct fu... |
2341 |
* If 3, cleanup and return -ERESTARTNOINTR. |
52400ba94 futex: add requeu... |
2342 2343 2344 2345 2346 2347 2348 |
* * If 2, we may then block on trying to take the rt_mutex and return via: * 5) successful lock * 6) signal * 7) timeout * 8) other lock acquisition failure * |
cc6db4e60 futex: Correct fu... |
2349 |
* If 6, return -EWOULDBLOCK (restarting the syscall would do the same). |
52400ba94 futex: add requeu... |
2350 2351 2352 |
* * If 4 or 7, we cleanup and return with -ETIMEDOUT. * |
6c23cbbd5 futex: fix kernel... |
2353 2354 |
* Return: * 0 - On success; |
52400ba94 futex: add requeu... |
2355 2356 |
* <0 - On error */ |
b41277dc7 futex: Replace fs... |
2357 |
static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, |
52400ba94 futex: add requeu... |
2358 |
u32 val, ktime_t *abs_time, u32 bitset, |
b41277dc7 futex: Replace fs... |
2359 |
u32 __user *uaddr2) |
52400ba94 futex: add requeu... |
2360 2361 2362 2363 |
{ struct hrtimer_sleeper timeout, *to = NULL; struct rt_mutex_waiter rt_waiter; struct rt_mutex *pi_mutex = NULL; |
52400ba94 futex: add requeu... |
2364 |
struct futex_hash_bucket *hb; |
5bdb05f91 futex: Add futex_... |
2365 2366 |
union futex_key key2 = FUTEX_KEY_INIT; struct futex_q q = futex_q_init; |
52400ba94 futex: add requeu... |
2367 |
int res, ret; |
52400ba94 futex: add requeu... |
2368 |
|
6f7b0a2a5 futex: Forbid uad... |
2369 2370 |
if (uaddr == uaddr2) return -EINVAL; |
52400ba94 futex: add requeu... |
2371 2372 2373 2374 2375 |
if (!bitset) return -EINVAL; if (abs_time) { to = &timeout; |
b41277dc7 futex: Replace fs... |
2376 2377 2378 |
hrtimer_init_on_stack(&to->timer, (flags & FLAGS_CLOCKRT) ? CLOCK_REALTIME : CLOCK_MONOTONIC, HRTIMER_MODE_ABS); |
52400ba94 futex: add requeu... |
2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 |
hrtimer_init_sleeper(to, current); hrtimer_set_expires_range_ns(&to->timer, *abs_time, current->timer_slack_ns); } /* * The waiter is allocated on our stack, manipulated by the requeue * code while we sleep on uaddr. */ debug_rt_mutex_init_waiter(&rt_waiter); |
fb00aca47 rtmutex: Turn the... |
2389 2390 |
RB_CLEAR_NODE(&rt_waiter.pi_tree_entry); RB_CLEAR_NODE(&rt_waiter.tree_entry); |
52400ba94 futex: add requeu... |
2391 |
rt_waiter.task = NULL; |
9ea71503a futex: Fix regres... |
2392 |
ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE); |
52400ba94 futex: add requeu... |
2393 2394 |
if (unlikely(ret != 0)) goto out; |
84bc4af59 futex: Detect mis... |
2395 2396 2397 |
q.bitset = bitset; q.rt_waiter = &rt_waiter; q.requeue_pi_key = &key2; |
7ada876a8 futex: Fix errors... |
2398 2399 2400 2401 |
/* * Prepare to wait on uaddr. On success, increments q.key (key1) ref * count. */ |
b41277dc7 futex: Replace fs... |
2402 |
ret = futex_wait_setup(uaddr, val, flags, &q, &hb); |
c8b15a706 futex: cleanup er... |
2403 2404 |
if (ret) goto out_key2; |
52400ba94 futex: add requeu... |
2405 2406 |
/* Queue the futex_q, drop the hb lock, wait for wakeup. */ |
f1a11e057 futex: remove the... |
2407 |
futex_wait_queue_me(hb, &q, to); |
52400ba94 futex: add requeu... |
2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 |
spin_lock(&hb->lock); ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to); spin_unlock(&hb->lock); if (ret) goto out_put_keys; /* * In order for us to be here, we know our q.key == key2, and since * we took the hb->lock above, we also know that futex_requeue() has * completed and we no longer have to concern ourselves with a wakeup |
7ada876a8 futex: Fix errors... |
2419 2420 2421 |
* race with the atomic proxy lock acquisition by the requeue code. The * futex_requeue dropped our key1 reference and incremented our key2 * reference count. |
52400ba94 futex: add requeu... |
2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 |
*/ /* Check if the requeue code acquired the second futex for us. */ if (!q.rt_waiter) { /* * Got the lock. We might not be the anticipated owner if we * did a lock-steal - fix up the PI-state in that case. */ if (q.pi_state && (q.pi_state->owner != current)) { spin_lock(q.lock_ptr); |
ae791a2d2 futex: Cleanup st... |
2432 |
ret = fixup_pi_state_owner(uaddr2, &q, current); |
52400ba94 futex: add requeu... |
2433 2434 2435 2436 2437 2438 2439 2440 |
spin_unlock(q.lock_ptr); } } else { /* * We have been woken up by futex_unlock_pi(), a timeout, or a * signal. futex_unlock_pi() will not destroy the lock_ptr nor * the pi_state. */ |
f27071cb7 futex: Fix bug in... |
2441 |
WARN_ON(!q.pi_state); |
52400ba94 futex: add requeu... |
2442 2443 2444 2445 2446 2447 2448 2449 2450 |
pi_mutex = &q.pi_state->pi_mutex; ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter, 1); debug_rt_mutex_free_waiter(&rt_waiter); spin_lock(q.lock_ptr); /* * Fixup the pi_state owner and possibly acquire the lock if we * haven't already. */ |
ae791a2d2 futex: Cleanup st... |
2451 |
res = fixup_owner(uaddr2, &q, !ret); |
52400ba94 futex: add requeu... |
2452 2453 |
/* * If fixup_owner() returned an error, proprogate that. If it |
56ec1607b futex: Correct fu... |
2454 |
* acquired the lock, clear -ETIMEDOUT or -EINTR. |
52400ba94 futex: add requeu... |
2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 |
*/ if (res) ret = (res < 0) ? res : 0; /* Unqueue and drop the lock. */ unqueue_me_pi(&q); } /* * If fixup_pi_state_owner() faulted and was unable to handle the * fault, unlock the rt_mutex and return the fault to userspace. */ if (ret == -EFAULT) { |
b6070a8d9 futex: Test for p... |
2468 |
if (pi_mutex && rt_mutex_owner(pi_mutex) == current) |
52400ba94 futex: add requeu... |
2469 2470 |
rt_mutex_unlock(pi_mutex); } else if (ret == -EINTR) { |
52400ba94 futex: add requeu... |
2471 |
/* |
cc6db4e60 futex: Correct fu... |
2472 2473 2474 2475 2476 |
* We've already been requeued, but cannot restart by calling * futex_lock_pi() directly. We could restart this syscall, but * it would detect that the user space "val" changed and return * -EWOULDBLOCK. Save the overhead of the restart and return * -EWOULDBLOCK directly. |
52400ba94 futex: add requeu... |
2477 |
*/ |
2070887fd futex: fix restar... |
2478 |
ret = -EWOULDBLOCK; |
52400ba94 futex: add requeu... |
2479 2480 2481 |
} out_put_keys: |
ae791a2d2 futex: Cleanup st... |
2482 |
put_futex_key(&q.key); |
c8b15a706 futex: cleanup er... |
2483 |
out_key2: |
ae791a2d2 futex: Cleanup st... |
2484 |
put_futex_key(&key2); |
52400ba94 futex: add requeu... |
2485 2486 2487 2488 2489 2490 2491 2492 |
out: if (to) { hrtimer_cancel(&to->timer); destroy_hrtimer_on_stack(&to->timer); } return ret; } |
0771dfefc [PATCH] lightweig... |
2493 2494 2495 2496 2497 2498 2499 |
/* * Support for robust futexes: the kernel cleans up held futexes at * thread exit time. * * Implementation: user-space maintains a per-thread list of locks it * is holding. Upon do_exit(), the kernel carefully walks this list, * and marks all locks that are owned by this thread with the |
c87e2837b [PATCH] pi-futex:... |
2500 |
* FUTEX_OWNER_DIED bit, and wakes up a waiter (if any). The list is |
0771dfefc [PATCH] lightweig... |
2501 2502 2503 2504 2505 2506 2507 2508 |
* always manipulated with the lock held, so the list is private and * per-thread. Userspace also maintains a per-thread 'list_op_pending' * field, to allow the kernel to clean up if the thread dies after * acquiring the lock, but just before it could have added itself to * the list. There can only be one such pending lock. */ /** |
d96ee56ce futex: Make funct... |
2509 2510 2511 |
* sys_set_robust_list() - Set the robust-futex list head of a task * @head: pointer to the list-head * @len: length of the list-head, as userspace expects |
0771dfefc [PATCH] lightweig... |
2512 |
*/ |
836f92adf [CVE-2009-0029] S... |
2513 2514 |
SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head, size_t, len) |
0771dfefc [PATCH] lightweig... |
2515 |
{ |
a0c1e9073 futex: runtime en... |
2516 2517 |
if (!futex_cmpxchg_enabled) return -ENOSYS; |
0771dfefc [PATCH] lightweig... |
2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 |
/* * The kernel knows only one size for now: */ if (unlikely(len != sizeof(*head))) return -EINVAL; current->robust_list = head; return 0; } /** |
d96ee56ce futex: Make funct... |
2530 2531 2532 2533 |
* sys_get_robust_list() - Get the robust-futex list head of a task * @pid: pid of the process [zero for current task] * @head_ptr: pointer to a list-head pointer, the kernel fills it in * @len_ptr: pointer to a length field, the kernel fills in the header size |
0771dfefc [PATCH] lightweig... |
2534 |
*/ |
836f92adf [CVE-2009-0029] S... |
2535 2536 2537 |
SYSCALL_DEFINE3(get_robust_list, int, pid, struct robust_list_head __user * __user *, head_ptr, size_t __user *, len_ptr) |
0771dfefc [PATCH] lightweig... |
2538 |
{ |
ba46df984 [PATCH] __user an... |
2539 |
struct robust_list_head __user *head; |
0771dfefc [PATCH] lightweig... |
2540 |
unsigned long ret; |
bdbb776f8 futex: Do not lea... |
2541 |
struct task_struct *p; |
0771dfefc [PATCH] lightweig... |
2542 |
|
a0c1e9073 futex: runtime en... |
2543 2544 |
if (!futex_cmpxchg_enabled) return -ENOSYS; |
bdbb776f8 futex: Do not lea... |
2545 2546 2547 |
rcu_read_lock(); ret = -ESRCH; |
0771dfefc [PATCH] lightweig... |
2548 |
if (!pid) |
bdbb776f8 futex: Do not lea... |
2549 |
p = current; |
0771dfefc [PATCH] lightweig... |
2550 |
else { |
228ebcbe6 Uninline find_tas... |
2551 |
p = find_task_by_vpid(pid); |
0771dfefc [PATCH] lightweig... |
2552 2553 |
if (!p) goto err_unlock; |
0771dfefc [PATCH] lightweig... |
2554 |
} |
bdbb776f8 futex: Do not lea... |
2555 2556 2557 2558 2559 2560 |
ret = -EPERM; if (!ptrace_may_access(p, PTRACE_MODE_READ)) goto err_unlock; head = p->robust_list; rcu_read_unlock(); |
0771dfefc [PATCH] lightweig... |
2561 2562 2563 2564 2565 |
if (put_user(sizeof(*head), len_ptr)) return -EFAULT; return put_user(head, head_ptr); err_unlock: |
aaa2a97eb [PATCH] sys_get_r... |
2566 |
rcu_read_unlock(); |
0771dfefc [PATCH] lightweig... |
2567 2568 2569 2570 2571 2572 2573 2574 |
return ret; } /* * Process a futex-list entry, check whether it's owned by the * dying task, and do notification if so: */ |
e3f2ddeac [PATCH] pi-futex:... |
2575 |
int handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi) |
0771dfefc [PATCH] lightweig... |
2576 |
{ |
7cfdaf38d futex: uninitiali... |
2577 |
u32 uval, uninitialized_var(nval), mval; |
0771dfefc [PATCH] lightweig... |
2578 |
|
8f17d3a50 [PATCH] lightweig... |
2579 2580 |
retry: if (get_user(uval, uaddr)) |
0771dfefc [PATCH] lightweig... |
2581 |
return -1; |
b488893a3 pid namespaces: c... |
2582 |
if ((uval & FUTEX_TID_MASK) == task_pid_vnr(curr)) { |
0771dfefc [PATCH] lightweig... |
2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 |
/* * Ok, this dying thread is truly holding a futex * of interest. Set the OWNER_DIED bit atomically * via cmpxchg, and if the value had FUTEX_WAITERS * set, wake up a waiter (if any). (We have to do a * futex_wake() even if OWNER_DIED is already set - * to handle the rare but possible case of recursive * thread-death.) The rest of the cleanup is done in * userspace. */ |
e3f2ddeac [PATCH] pi-futex:... |
2593 |
mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; |
6e0aa9f8a futex: Deobfuscat... |
2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 |
/* * We are not holding a lock here, but we want to have * the pagefault_disable/enable() protection because * we want to handle the fault gracefully. If the * access fails we try to fault in the futex with R/W * verification via get_user_pages. get_user() above * does not guarantee R/W access. If that fails we * give up and leave the futex locked. */ if (cmpxchg_futex_value_locked(&nval, uaddr, uval, mval)) { if (fault_in_user_writeable(uaddr)) return -1; goto retry; } |
c87e2837b [PATCH] pi-futex:... |
2608 |
if (nval != uval) |
8f17d3a50 [PATCH] lightweig... |
2609 |
goto retry; |
0771dfefc [PATCH] lightweig... |
2610 |
|
e3f2ddeac [PATCH] pi-futex:... |
2611 2612 2613 2614 |
/* * Wake robust non-PI futexes here. The wakeup of * PI futexes happens in exit_pi_state(): */ |
36cf3b5c3 FUTEX: Tidy up th... |
2615 |
if (!pi && (uval & FUTEX_WAITERS)) |
c2f9f2015 futex: cleanup fs... |
2616 |
futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY); |
0771dfefc [PATCH] lightweig... |
2617 2618 2619 2620 2621 |
} return 0; } /* |
e3f2ddeac [PATCH] pi-futex:... |
2622 2623 2624 |
* Fetch a robust-list pointer. Bit 0 signals PI futexes: */ static inline int fetch_robust_entry(struct robust_list __user **entry, |
ba46df984 [PATCH] __user an... |
2625 |
struct robust_list __user * __user *head, |
1dcc41bb0 futex: Change 3rd... |
2626 |
unsigned int *pi) |
e3f2ddeac [PATCH] pi-futex:... |
2627 2628 |
{ unsigned long uentry; |
ba46df984 [PATCH] __user an... |
2629 |
if (get_user(uentry, (unsigned long __user *)head)) |
e3f2ddeac [PATCH] pi-futex:... |
2630 |
return -EFAULT; |
ba46df984 [PATCH] __user an... |
2631 |
*entry = (void __user *)(uentry & ~1UL); |
e3f2ddeac [PATCH] pi-futex:... |
2632 2633 2634 2635 2636 2637 |
*pi = uentry & 1; return 0; } /* |
0771dfefc [PATCH] lightweig... |
2638 2639 2640 2641 2642 2643 2644 2645 |
* Walk curr->robust_list (very carefully, it's a userspace list!) * and mark any locks found there dead, and notify any waiters. * * We silently return on any sign of list-walking problem. */ void exit_robust_list(struct task_struct *curr) { struct robust_list_head __user *head = curr->robust_list; |
9f96cb1e8 robust futex thre... |
2646 |
struct robust_list __user *entry, *next_entry, *pending; |
4c115e951 futex: Address co... |
2647 2648 |
unsigned int limit = ROBUST_LIST_LIMIT, pi, pip; unsigned int uninitialized_var(next_pi); |
0771dfefc [PATCH] lightweig... |
2649 |
unsigned long futex_offset; |
9f96cb1e8 robust futex thre... |
2650 |
int rc; |
0771dfefc [PATCH] lightweig... |
2651 |
|
a0c1e9073 futex: runtime en... |
2652 2653 |
if (!futex_cmpxchg_enabled) return; |
0771dfefc [PATCH] lightweig... |
2654 2655 2656 2657 |
/* * Fetch the list head (which was registered earlier, via * sys_set_robust_list()): */ |
e3f2ddeac [PATCH] pi-futex:... |
2658 |
if (fetch_robust_entry(&entry, &head->list.next, &pi)) |
0771dfefc [PATCH] lightweig... |
2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 |
return; /* * Fetch the relative futex offset: */ if (get_user(futex_offset, &head->futex_offset)) return; /* * Fetch any possibly pending lock-add first, and handle it * if it exists: */ |
e3f2ddeac [PATCH] pi-futex:... |
2669 |
if (fetch_robust_entry(&pending, &head->list_op_pending, &pip)) |
0771dfefc [PATCH] lightweig... |
2670 |
return; |
e3f2ddeac [PATCH] pi-futex:... |
2671 |
|
9f96cb1e8 robust futex thre... |
2672 |
next_entry = NULL; /* avoid warning with gcc */ |
0771dfefc [PATCH] lightweig... |
2673 2674 |
while (entry != &head->list) { /* |
9f96cb1e8 robust futex thre... |
2675 2676 2677 2678 2679 |
* Fetch the next entry in the list before calling * handle_futex_death: */ rc = fetch_robust_entry(&next_entry, &entry->next, &next_pi); /* |
0771dfefc [PATCH] lightweig... |
2680 |
* A pending lock might already be on the list, so |
c87e2837b [PATCH] pi-futex:... |
2681 |
* don't process it twice: |
0771dfefc [PATCH] lightweig... |
2682 2683 |
*/ if (entry != pending) |
ba46df984 [PATCH] __user an... |
2684 |
if (handle_futex_death((void __user *)entry + futex_offset, |
e3f2ddeac [PATCH] pi-futex:... |
2685 |
curr, pi)) |
0771dfefc [PATCH] lightweig... |
2686 |
return; |
9f96cb1e8 robust futex thre... |
2687 |
if (rc) |
0771dfefc [PATCH] lightweig... |
2688 |
return; |
9f96cb1e8 robust futex thre... |
2689 2690 |
entry = next_entry; pi = next_pi; |
0771dfefc [PATCH] lightweig... |
2691 2692 2693 2694 2695 2696 2697 2698 |
/* * Avoid excessively long or circular lists: */ if (!--limit) break; cond_resched(); } |
9f96cb1e8 robust futex thre... |
2699 2700 2701 2702 |
if (pending) handle_futex_death((void __user *)pending + futex_offset, curr, pip); |
0771dfefc [PATCH] lightweig... |
2703 |
} |
c19384b5b Make futex_wait()... |
2704 |
long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, |
e2970f2fb [PATCH] pi-futex:... |
2705 |
u32 __user *uaddr2, u32 val2, u32 val3) |
1da177e4c Linux-2.6.12-rc2 |
2706 |
{ |
81b40539e futex: Simplify r... |
2707 |
int cmd = op & FUTEX_CMD_MASK; |
b41277dc7 futex: Replace fs... |
2708 |
unsigned int flags = 0; |
34f01cc1f FUTEX: new PRIVAT... |
2709 2710 |
if (!(op & FUTEX_PRIVATE_FLAG)) |
b41277dc7 futex: Replace fs... |
2711 |
flags |= FLAGS_SHARED; |
1da177e4c Linux-2.6.12-rc2 |
2712 |
|
b41277dc7 futex: Replace fs... |
2713 2714 2715 2716 2717 |
if (op & FUTEX_CLOCK_REALTIME) { flags |= FLAGS_CLOCKRT; if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI) return -ENOSYS; } |
1da177e4c Linux-2.6.12-rc2 |
2718 |
|
34f01cc1f FUTEX: new PRIVAT... |
2719 |
switch (cmd) { |
59263b513 futex: Cover all ... |
2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 |
case FUTEX_LOCK_PI: case FUTEX_UNLOCK_PI: case FUTEX_TRYLOCK_PI: case FUTEX_WAIT_REQUEUE_PI: case FUTEX_CMP_REQUEUE_PI: if (!futex_cmpxchg_enabled) return -ENOSYS; } switch (cmd) { |
1da177e4c Linux-2.6.12-rc2 |
2730 |
case FUTEX_WAIT: |
cd689985c futex: Add bitset... |
2731 2732 |
val3 = FUTEX_BITSET_MATCH_ANY; case FUTEX_WAIT_BITSET: |
81b40539e futex: Simplify r... |
2733 |
return futex_wait(uaddr, flags, val, timeout, val3); |
1da177e4c Linux-2.6.12-rc2 |
2734 |
case FUTEX_WAKE: |
cd689985c futex: Add bitset... |
2735 2736 |
val3 = FUTEX_BITSET_MATCH_ANY; case FUTEX_WAKE_BITSET: |
81b40539e futex: Simplify r... |
2737 |
return futex_wake(uaddr, flags, val, val3); |
1da177e4c Linux-2.6.12-rc2 |
2738 |
case FUTEX_REQUEUE: |
81b40539e futex: Simplify r... |
2739 |
return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0); |
1da177e4c Linux-2.6.12-rc2 |
2740 |
case FUTEX_CMP_REQUEUE: |
81b40539e futex: Simplify r... |
2741 |
return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0); |
4732efbeb [PATCH] FUTEX_WAK... |
2742 |
case FUTEX_WAKE_OP: |
81b40539e futex: Simplify r... |
2743 |
return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3); |
c87e2837b [PATCH] pi-futex:... |
2744 |
case FUTEX_LOCK_PI: |
81b40539e futex: Simplify r... |
2745 |
return futex_lock_pi(uaddr, flags, val, timeout, 0); |
c87e2837b [PATCH] pi-futex:... |
2746 |
case FUTEX_UNLOCK_PI: |
81b40539e futex: Simplify r... |
2747 |
return futex_unlock_pi(uaddr, flags); |
c87e2837b [PATCH] pi-futex:... |
2748 |
case FUTEX_TRYLOCK_PI: |
81b40539e futex: Simplify r... |
2749 |
return futex_lock_pi(uaddr, flags, 0, timeout, 1); |
52400ba94 futex: add requeu... |
2750 2751 |
case FUTEX_WAIT_REQUEUE_PI: val3 = FUTEX_BITSET_MATCH_ANY; |
81b40539e futex: Simplify r... |
2752 2753 |
return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3, uaddr2); |
52400ba94 futex: add requeu... |
2754 |
case FUTEX_CMP_REQUEUE_PI: |
81b40539e futex: Simplify r... |
2755 |
return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1); |
1da177e4c Linux-2.6.12-rc2 |
2756 |
} |
81b40539e futex: Simplify r... |
2757 |
return -ENOSYS; |
1da177e4c Linux-2.6.12-rc2 |
2758 |
} |
17da2bd90 [CVE-2009-0029] S... |
2759 2760 2761 |
SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, struct timespec __user *, utime, u32 __user *, uaddr2, u32, val3) |
1da177e4c Linux-2.6.12-rc2 |
2762 |
{ |
c19384b5b Make futex_wait()... |
2763 2764 |
struct timespec ts; ktime_t t, *tp = NULL; |
e2970f2fb [PATCH] pi-futex:... |
2765 |
u32 val2 = 0; |
34f01cc1f FUTEX: new PRIVAT... |
2766 |
int cmd = op & FUTEX_CMD_MASK; |
1da177e4c Linux-2.6.12-rc2 |
2767 |
|
cd689985c futex: Add bitset... |
2768 |
if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI || |
52400ba94 futex: add requeu... |
2769 2770 |
cmd == FUTEX_WAIT_BITSET || cmd == FUTEX_WAIT_REQUEUE_PI)) { |
c19384b5b Make futex_wait()... |
2771 |
if (copy_from_user(&ts, utime, sizeof(ts)) != 0) |
1da177e4c Linux-2.6.12-rc2 |
2772 |
return -EFAULT; |
c19384b5b Make futex_wait()... |
2773 |
if (!timespec_valid(&ts)) |
9741ef964 [PATCH] futex: ch... |
2774 |
return -EINVAL; |
c19384b5b Make futex_wait()... |
2775 2776 |
t = timespec_to_ktime(ts); |
34f01cc1f FUTEX: new PRIVAT... |
2777 |
if (cmd == FUTEX_WAIT) |
5a7780e72 hrtimer: check re... |
2778 |
t = ktime_add_safe(ktime_get(), t); |
c19384b5b Make futex_wait()... |
2779 |
tp = &t; |
1da177e4c Linux-2.6.12-rc2 |
2780 2781 |
} /* |
52400ba94 futex: add requeu... |
2782 |
* requeue parameter in 'utime' if cmd == FUTEX_*_REQUEUE_*. |
f54f09861 futex: pass nr_wa... |
2783 |
* number of waiters to wake in 'utime' if cmd == FUTEX_WAKE_OP. |
1da177e4c Linux-2.6.12-rc2 |
2784 |
*/ |
f54f09861 futex: pass nr_wa... |
2785 |
if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE || |
ba9c22f2c futex: remove FUT... |
2786 |
cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP) |
e2970f2fb [PATCH] pi-futex:... |
2787 |
val2 = (u32) (unsigned long) utime; |
1da177e4c Linux-2.6.12-rc2 |
2788 |
|
c19384b5b Make futex_wait()... |
2789 |
return do_futex(uaddr, op, val, tp, uaddr2, val2, val3); |
1da177e4c Linux-2.6.12-rc2 |
2790 |
} |
03b8c7b62 futex: Allow arch... |
2791 |
static void __init futex_detect_cmpxchg(void) |
1da177e4c Linux-2.6.12-rc2 |
2792 |
{ |
03b8c7b62 futex: Allow arch... |
2793 |
#ifndef CONFIG_HAVE_FUTEX_CMPXCHG |
a0c1e9073 futex: runtime en... |
2794 |
u32 curval; |
03b8c7b62 futex: Allow arch... |
2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 |
/* * This will fail and we want it. Some arch implementations do * runtime detection of the futex_atomic_cmpxchg_inatomic() * functionality. We want to know that before we call in any * of the complex code paths. Also we want to prevent * registration of robust lists in that case. NULL is * guaranteed to fault and we get -EFAULT on functional * implementation, the non-functional ones will return * -ENOSYS. */ if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT) futex_cmpxchg_enabled = 1; #endif } static int __init futex_init(void) { |
63b1a8169 futexes: Fix fute... |
2813 |
unsigned int futex_shift; |
a52b89ebb futexes: Increase... |
2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 |
unsigned long i; #if CONFIG_BASE_SMALL futex_hashsize = 16; #else futex_hashsize = roundup_pow_of_two(256 * num_possible_cpus()); #endif futex_queues = alloc_large_system_hash("futex", sizeof(*futex_queues), futex_hashsize, 0, futex_hashsize < 256 ? HASH_SMALL : 0, |
63b1a8169 futexes: Fix fute... |
2825 2826 2827 |
&futex_shift, NULL, futex_hashsize, futex_hashsize); futex_hashsize = 1UL << futex_shift; |
03b8c7b62 futex: Allow arch... |
2828 2829 |
futex_detect_cmpxchg(); |
a0c1e9073 futex: runtime en... |
2830 |
|
a52b89ebb futexes: Increase... |
2831 |
for (i = 0; i < futex_hashsize; i++) { |
11d4616bd futex: revert bac... |
2832 |
atomic_set(&futex_queues[i].waiters, 0); |
732375c6a plist: Remove the... |
2833 |
plist_head_init(&futex_queues[i].chain); |
3e4ab747e futex: fix init o... |
2834 2835 |
spin_lock_init(&futex_queues[i].lock); } |
1da177e4c Linux-2.6.12-rc2 |
2836 2837 |
return 0; } |
f6d107fb1 Give futex init a... |
2838 |
__initcall(futex_init); |