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kernel/kprobes.c
64.3 KB
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// SPDX-License-Identifier: GPL-2.0-or-later |
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/* * Kernel Probes (KProbes) * kernel/kprobes.c * |
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* Copyright (C) IBM Corporation, 2002, 2004 * * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel * Probes initial implementation (includes suggestions from * Rusty Russell). * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with * hlists and exceptions notifier as suggested by Andi Kleen. * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes * interface to access function arguments. * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes * exceptions notifier to be first on the priority list. |
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* 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi * <prasanna@in.ibm.com> added function-return probes. |
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*/ #include <linux/kprobes.h> |
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#include <linux/hash.h> #include <linux/init.h> |
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#include <linux/slab.h> |
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#include <linux/stddef.h> |
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#include <linux/export.h> |
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#include <linux/moduleloader.h> |
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#include <linux/kallsyms.h> |
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#include <linux/freezer.h> |
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#include <linux/seq_file.h> #include <linux/debugfs.h> |
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#include <linux/sysctl.h> |
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#include <linux/kdebug.h> |
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#include <linux/memory.h> |
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#include <linux/ftrace.h> |
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#include <linux/cpu.h> |
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#include <linux/jump_label.h> |
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|
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#include <asm/sections.h> |
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#include <asm/cacheflush.h> #include <asm/errno.h> |
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#include <linux/uaccess.h> |
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#define KPROBE_HASH_BITS 6 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) |
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static int kprobes_initialized; |
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static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; |
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static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; |
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|
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/* NOTE: change this value only with kprobe_mutex held */ |
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static bool kprobes_all_disarmed; |
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/* This protects kprobe_table and optimizing_list */ static DEFINE_MUTEX(kprobe_mutex); |
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static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; |
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static struct { |
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raw_spinlock_t lock ____cacheline_aligned_in_smp; |
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} kretprobe_table_locks[KPROBE_TABLE_SIZE]; |
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kprobe_opcode_t * __weak kprobe_lookup_name(const char *name, unsigned int __unused) |
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{ return ((kprobe_opcode_t *)(kallsyms_lookup_name(name))); } |
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static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) |
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{ return &(kretprobe_table_locks[hash].lock); } |
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/* Blacklist -- list of struct kprobe_blacklist_entry */ static LIST_HEAD(kprobe_blacklist); |
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|
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#ifdef __ARCH_WANT_KPROBES_INSN_SLOT |
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/* * kprobe->ainsn.insn points to the copy of the instruction to be * single-stepped. x86_64, POWER4 and above have no-exec support and * stepping on the instruction on a vmalloced/kmalloced/data page * is a recipe for disaster */ |
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struct kprobe_insn_page { |
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struct list_head list; |
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kprobe_opcode_t *insns; /* Page of instruction slots */ |
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struct kprobe_insn_cache *cache; |
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int nused; |
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int ngarbage; |
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char slot_used[]; |
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}; |
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#define KPROBE_INSN_PAGE_SIZE(slots) \ (offsetof(struct kprobe_insn_page, slot_used) + \ (sizeof(char) * (slots))) |
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static int slots_per_page(struct kprobe_insn_cache *c) { return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); } |
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enum kprobe_slot_state { SLOT_CLEAN = 0, SLOT_DIRTY = 1, SLOT_USED = 2, }; |
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void __weak *alloc_insn_page(void) |
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{ return module_alloc(PAGE_SIZE); } |
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void __weak free_insn_page(void *page) |
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{ |
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module_memfree(page); |
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} |
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struct kprobe_insn_cache kprobe_insn_slots = { .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), |
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.alloc = alloc_insn_page, .free = free_insn_page, |
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.pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), .insn_size = MAX_INSN_SIZE, .nr_garbage = 0, }; |
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static int collect_garbage_slots(struct kprobe_insn_cache *c); |
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|
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/** |
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* __get_insn_slot() - Find a slot on an executable page for an instruction. |
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* We allocate an executable page if there's no room on existing ones. */ |
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kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) |
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{ struct kprobe_insn_page *kip; |
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kprobe_opcode_t *slot = NULL; |
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|
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/* Since the slot array is not protected by rcu, we need a mutex */ |
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mutex_lock(&c->mutex); |
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retry: |
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rcu_read_lock(); list_for_each_entry_rcu(kip, &c->pages, list) { |
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if (kip->nused < slots_per_page(c)) { |
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int i; |
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for (i = 0; i < slots_per_page(c); i++) { |
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if (kip->slot_used[i] == SLOT_CLEAN) { kip->slot_used[i] = SLOT_USED; |
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kip->nused++; |
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slot = kip->insns + (i * c->insn_size); |
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rcu_read_unlock(); |
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goto out; |
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} } |
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/* kip->nused is broken. Fix it. */ kip->nused = slots_per_page(c); WARN_ON(1); |
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} } |
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rcu_read_unlock(); |
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/* If there are any garbage slots, collect it and try again. */ |
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if (c->nr_garbage && collect_garbage_slots(c) == 0) |
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goto retry; |
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/* All out of space. Need to allocate a new page. */ kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); |
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if (!kip) |
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goto out; |
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/* * Use module_alloc so this page is within +/- 2GB of where the * kernel image and loaded module images reside. This is required * so x86_64 can correctly handle the %rip-relative fixups. */ |
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kip->insns = c->alloc(); |
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if (!kip->insns) { kfree(kip); |
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goto out; |
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} |
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INIT_LIST_HEAD(&kip->list); |
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memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c)); |
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kip->slot_used[0] = SLOT_USED; |
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kip->nused = 1; |
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kip->ngarbage = 0; |
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kip->cache = c; |
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list_add_rcu(&kip->list, &c->pages); |
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slot = kip->insns; out: mutex_unlock(&c->mutex); return slot; |
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} |
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/* Return 1 if all garbages are collected, otherwise 0. */ |
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static int collect_one_slot(struct kprobe_insn_page *kip, int idx) |
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{ |
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kip->slot_used[idx] = SLOT_CLEAN; |
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kip->nused--; if (kip->nused == 0) { /* * Page is no longer in use. Free it unless * it's the last one. We keep the last one * so as not to have to set it up again the * next time somebody inserts a probe. */ |
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if (!list_is_singular(&kip->list)) { |
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list_del_rcu(&kip->list); synchronize_rcu(); |
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kip->cache->free(kip->insns); |
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kfree(kip); } return 1; } return 0; } |
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static int collect_garbage_slots(struct kprobe_insn_cache *c) |
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{ |
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struct kprobe_insn_page *kip, *next; |
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/* Ensure no-one is interrupted on the garbages */ |
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synchronize_rcu(); |
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list_for_each_entry_safe(kip, next, &c->pages, list) { |
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int i; |
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if (kip->ngarbage == 0) continue; kip->ngarbage = 0; /* we will collect all garbages */ |
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for (i = 0; i < slots_per_page(c); i++) { |
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if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i)) |
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break; } } |
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c->nr_garbage = 0; |
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return 0; } |
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void __free_insn_slot(struct kprobe_insn_cache *c, kprobe_opcode_t *slot, int dirty) |
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{ struct kprobe_insn_page *kip; |
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long idx; |
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mutex_lock(&c->mutex); |
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rcu_read_lock(); list_for_each_entry_rcu(kip, &c->pages, list) { idx = ((long)slot - (long)kip->insns) / (c->insn_size * sizeof(kprobe_opcode_t)); if (idx >= 0 && idx < slots_per_page(c)) |
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goto out; |
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} |
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/* Could not find this slot. */ |
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WARN_ON(1); |
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kip = NULL; |
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out: |
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rcu_read_unlock(); /* Mark and sweep: this may sleep */ if (kip) { /* Check double free */ WARN_ON(kip->slot_used[idx] != SLOT_USED); if (dirty) { kip->slot_used[idx] = SLOT_DIRTY; kip->ngarbage++; if (++c->nr_garbage > slots_per_page(c)) collect_garbage_slots(c); } else { collect_one_slot(kip, idx); } } |
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mutex_unlock(&c->mutex); |
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} |
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/* * Check given address is on the page of kprobe instruction slots. * This will be used for checking whether the address on a stack * is on a text area or not. */ bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr) { struct kprobe_insn_page *kip; bool ret = false; rcu_read_lock(); list_for_each_entry_rcu(kip, &c->pages, list) { if (addr >= (unsigned long)kip->insns && addr < (unsigned long)kip->insns + PAGE_SIZE) { ret = true; break; } } rcu_read_unlock(); return ret; } |
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#ifdef CONFIG_OPTPROBES /* For optimized_kprobe buffer */ |
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struct kprobe_insn_cache kprobe_optinsn_slots = { .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), |
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.alloc = alloc_insn_page, .free = free_insn_page, |
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.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), /* .insn_size is initialized later */ .nr_garbage = 0, }; |
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#endif |
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#endif |
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/* We have preemption disabled.. so it is safe to use __ versions */ static inline void set_kprobe_instance(struct kprobe *kp) { |
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__this_cpu_write(kprobe_instance, kp); |
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} static inline void reset_kprobe_instance(void) { |
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__this_cpu_write(kprobe_instance, NULL); |
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} |
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/* * This routine is called either: |
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* - under the kprobe_mutex - during kprobe_[un]register() |
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* OR |
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* - with preemption disabled - from arch/xxx/kernel/kprobes.c |
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*/ |
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struct kprobe *get_kprobe(void *addr) |
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{ struct hlist_head *head; |
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struct kprobe *p; |
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head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; |
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hlist_for_each_entry_rcu(p, head, hlist, lockdep_is_held(&kprobe_mutex)) { |
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if (p->addr == addr) return p; } |
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return NULL; } |
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NOKPROBE_SYMBOL(get_kprobe); |
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static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs); |
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/* Return true if the kprobe is an aggregator */ static inline int kprobe_aggrprobe(struct kprobe *p) { return p->pre_handler == aggr_pre_handler; } |
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/* Return true(!0) if the kprobe is unused */ static inline int kprobe_unused(struct kprobe *p) { return kprobe_aggrprobe(p) && kprobe_disabled(p) && list_empty(&p->list); } |
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/* * Keep all fields in the kprobe consistent */ |
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static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p) |
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{ |
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memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t)); memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn)); |
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} #ifdef CONFIG_OPTPROBES |
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/* NOTE: change this value only with kprobe_mutex held */ static bool kprobes_allow_optimization; |
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/* * Call all pre_handler on the list, but ignores its return value. * This must be called from arch-dep optimized caller. */ |
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void opt_pre_handler(struct kprobe *p, struct pt_regs *regs) |
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{ struct kprobe *kp; list_for_each_entry_rcu(kp, &p->list, list) { if (kp->pre_handler && likely(!kprobe_disabled(kp))) { set_kprobe_instance(kp); |
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kp->pre_handler(kp, regs); |
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} reset_kprobe_instance(); } } |
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NOKPROBE_SYMBOL(opt_pre_handler); |
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/* Free optimized instructions and optimized_kprobe */ |
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static void free_aggr_kprobe(struct kprobe *p) |
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{ struct optimized_kprobe *op; op = container_of(p, struct optimized_kprobe, kp); arch_remove_optimized_kprobe(op); arch_remove_kprobe(p); kfree(op); } |
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/* Return true(!0) if the kprobe is ready for optimization. */ static inline int kprobe_optready(struct kprobe *p) { struct optimized_kprobe *op; if (kprobe_aggrprobe(p)) { op = container_of(p, struct optimized_kprobe, kp); return arch_prepared_optinsn(&op->optinsn); } return 0; } |
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/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */ static inline int kprobe_disarmed(struct kprobe *p) { struct optimized_kprobe *op; /* If kprobe is not aggr/opt probe, just return kprobe is disabled */ if (!kprobe_aggrprobe(p)) return kprobe_disabled(p); op = container_of(p, struct optimized_kprobe, kp); return kprobe_disabled(p) && list_empty(&op->list); } /* Return true(!0) if the probe is queued on (un)optimizing lists */ |
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static int kprobe_queued(struct kprobe *p) |
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{ struct optimized_kprobe *op; if (kprobe_aggrprobe(p)) { op = container_of(p, struct optimized_kprobe, kp); if (!list_empty(&op->list)) return 1; } return 0; } |
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/* * Return an optimized kprobe whose optimizing code replaces * instructions including addr (exclude breakpoint). */ |
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static struct kprobe *get_optimized_kprobe(unsigned long addr) |
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{ int i; struct kprobe *p = NULL; struct optimized_kprobe *op; /* Don't check i == 0, since that is a breakpoint case. */ for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++) p = get_kprobe((void *)(addr - i)); if (p && kprobe_optready(p)) { op = container_of(p, struct optimized_kprobe, kp); if (arch_within_optimized_kprobe(op, addr)) return p; } return NULL; } /* Optimization staging list, protected by kprobe_mutex */ static LIST_HEAD(optimizing_list); |
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static LIST_HEAD(unoptimizing_list); |
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static LIST_HEAD(freeing_list); |
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static void kprobe_optimizer(struct work_struct *work); static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer); #define OPTIMIZE_DELAY 5 |
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/* * Optimize (replace a breakpoint with a jump) kprobes listed on * optimizing_list. */ |
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static void do_optimize_kprobes(void) |
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{ |
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lockdep_assert_held(&text_mutex); |
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/* * The optimization/unoptimization refers online_cpus via * stop_machine() and cpu-hotplug modifies online_cpus. * And same time, text_mutex will be held in cpu-hotplug and here. * This combination can cause a deadlock (cpu-hotplug try to lock * text_mutex but stop_machine can not be done because online_cpus * has been changed) |
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|
461 |
* To avoid this deadlock, caller must have locked cpu hotplug |
afd66255b
|
462 463 |
* for preventing cpu-hotplug outside of text_mutex locking. */ |
2d1e38f56
|
464 465 466 467 468 469 |
lockdep_assert_cpus_held(); /* Optimization never be done when disarmed */ if (kprobes_all_disarmed || !kprobes_allow_optimization || list_empty(&optimizing_list)) return; |
cd7ebe229
|
470 |
arch_optimize_kprobes(&optimizing_list); |
61f4e13ff
|
471 |
} |
6274de498
|
472 473 474 475 |
/* * Unoptimize (replace a jump with a breakpoint and remove the breakpoint * if need) kprobes listed on unoptimizing_list. */ |
55479f647
|
476 |
static void do_unoptimize_kprobes(void) |
6274de498
|
477 478 |
{ struct optimized_kprobe *op, *tmp; |
f1c6ece23
|
479 |
lockdep_assert_held(&text_mutex); |
2d1e38f56
|
480 481 |
/* See comment in do_optimize_kprobes() */ lockdep_assert_cpus_held(); |
6274de498
|
482 483 484 |
/* Unoptimization must be done anytime */ if (list_empty(&unoptimizing_list)) return; |
7b959fc58
|
485 |
arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); |
f984ba4eb
|
486 |
/* Loop free_list for disarming */ |
7b959fc58
|
487 |
list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
74c515e04
|
488 489 |
/* Switching from detour code to origin */ op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
6274de498
|
490 491 492 493 494 495 496 497 498 499 |
/* Disarm probes if marked disabled */ if (kprobe_disabled(&op->kp)) arch_disarm_kprobe(&op->kp); if (kprobe_unused(&op->kp)) { /* * Remove unused probes from hash list. After waiting * for synchronization, these probes are reclaimed. * (reclaiming is done by do_free_cleaned_kprobes.) */ hlist_del_rcu(&op->kp.hlist); |
6274de498
|
500 501 502 |
} else list_del_init(&op->list); } |
6274de498
|
503 504 505 |
} /* Reclaim all kprobes on the free_list */ |
55479f647
|
506 |
static void do_free_cleaned_kprobes(void) |
6274de498
|
507 508 |
{ struct optimized_kprobe *op, *tmp; |
7b959fc58
|
509 |
list_for_each_entry_safe(op, tmp, &freeing_list, list) { |
6274de498
|
510 |
list_del_init(&op->list); |
cbdd96f55
|
511 512 513 514 515 516 517 |
if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) { /* * This must not happen, but if there is a kprobe * still in use, keep it on kprobes hash list. */ continue; } |
6274de498
|
518 519 520 521 522 |
free_aggr_kprobe(&op->kp); } } /* Start optimizer after OPTIMIZE_DELAY passed */ |
55479f647
|
523 |
static void kick_kprobe_optimizer(void) |
6274de498
|
524 |
{ |
ad72b3bea
|
525 |
schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY); |
6274de498
|
526 |
} |
61f4e13ff
|
527 |
/* Kprobe jump optimizer */ |
55479f647
|
528 |
static void kprobe_optimizer(struct work_struct *work) |
61f4e13ff
|
529 |
{ |
72ef3794c
|
530 |
mutex_lock(&kprobe_mutex); |
2d1e38f56
|
531 |
cpus_read_lock(); |
f1c6ece23
|
532 |
mutex_lock(&text_mutex); |
61f4e13ff
|
533 534 |
/* Lock modules while optimizing kprobes */ mutex_lock(&module_mutex); |
61f4e13ff
|
535 536 |
/* |
6274de498
|
537 538 539 |
* Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) * kprobes before waiting for quiesence period. */ |
7b959fc58
|
540 |
do_unoptimize_kprobes(); |
6274de498
|
541 542 |
/* |
a30b85df7
|
543 544 545 546 547 548 549 |
* Step 2: Wait for quiesence period to ensure all potentially * preempted tasks to have normally scheduled. Because optprobe * may modify multiple instructions, there is a chance that Nth * instruction is preempted. In that case, such tasks can return * to 2nd-Nth byte of jump instruction. This wait is for avoiding it. * Note that on non-preemptive kernel, this is transparently converted * to synchronoze_sched() to wait for all interrupts to have completed. |
61f4e13ff
|
550 |
*/ |
a30b85df7
|
551 |
synchronize_rcu_tasks(); |
61f4e13ff
|
552 |
|
6274de498
|
553 |
/* Step 3: Optimize kprobes after quiesence period */ |
61f4e13ff
|
554 |
do_optimize_kprobes(); |
6274de498
|
555 556 |
/* Step 4: Free cleaned kprobes after quiesence period */ |
7b959fc58
|
557 |
do_free_cleaned_kprobes(); |
6274de498
|
558 |
|
afd66255b
|
559 |
mutex_unlock(&module_mutex); |
f1c6ece23
|
560 |
mutex_unlock(&text_mutex); |
2d1e38f56
|
561 |
cpus_read_unlock(); |
6274de498
|
562 |
|
cd7ebe229
|
563 |
/* Step 5: Kick optimizer again if needed */ |
f984ba4eb
|
564 |
if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) |
cd7ebe229
|
565 |
kick_kprobe_optimizer(); |
c19f0c3c9
|
566 567 |
mutex_unlock(&kprobe_mutex); |
6274de498
|
568 569 570 |
} /* Wait for completing optimization and unoptimization */ |
30e7d894c
|
571 |
void wait_for_kprobe_optimizer(void) |
6274de498
|
572 |
{ |
ad72b3bea
|
573 574 575 576 577 578 579 580 581 582 583 584 585 586 |
mutex_lock(&kprobe_mutex); while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) { mutex_unlock(&kprobe_mutex); /* this will also make optimizing_work execute immmediately */ flush_delayed_work(&optimizing_work); /* @optimizing_work might not have been queued yet, relax */ cpu_relax(); mutex_lock(&kprobe_mutex); } mutex_unlock(&kprobe_mutex); |
afd66255b
|
587 |
} |
4771b3f60
|
588 589 590 591 592 593 594 595 596 597 598 |
static bool optprobe_queued_unopt(struct optimized_kprobe *op) { struct optimized_kprobe *_op; list_for_each_entry(_op, &unoptimizing_list, list) { if (op == _op) return true; } return false; } |
afd66255b
|
599 |
/* Optimize kprobe if p is ready to be optimized */ |
55479f647
|
600 |
static void optimize_kprobe(struct kprobe *p) |
afd66255b
|
601 602 603 604 |
{ struct optimized_kprobe *op; /* Check if the kprobe is disabled or not ready for optimization. */ |
b2be84df9
|
605 |
if (!kprobe_optready(p) || !kprobes_allow_optimization || |
afd66255b
|
606 607 |
(kprobe_disabled(p) || kprobes_all_disarmed)) return; |
059053a27
|
608 609 |
/* kprobes with post_handler can not be optimized */ if (p->post_handler) |
afd66255b
|
610 611 612 613 614 615 616 617 618 |
return; op = container_of(p, struct optimized_kprobe, kp); /* Check there is no other kprobes at the optimized instructions */ if (arch_check_optimized_kprobe(op) < 0) return; /* Check if it is already optimized. */ |
4771b3f60
|
619 620 621 622 623 |
if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) { if (optprobe_queued_unopt(op)) { /* This is under unoptimizing. Just dequeue the probe */ list_del_init(&op->list); } |
afd66255b
|
624 |
return; |
4771b3f60
|
625 |
} |
afd66255b
|
626 |
op->kp.flags |= KPROBE_FLAG_OPTIMIZED; |
6274de498
|
627 |
|
4771b3f60
|
628 629 630 631 632 633 |
/* On unoptimizing/optimizing_list, op must have OPTIMIZED flag */ if (WARN_ON_ONCE(!list_empty(&op->list))) return; list_add(&op->list, &optimizing_list); kick_kprobe_optimizer(); |
6274de498
|
634 635 636 |
} /* Short cut to direct unoptimizing */ |
55479f647
|
637 |
static void force_unoptimize_kprobe(struct optimized_kprobe *op) |
6274de498
|
638 |
{ |
2d1e38f56
|
639 |
lockdep_assert_cpus_held(); |
6274de498
|
640 |
arch_unoptimize_kprobe(op); |
74c515e04
|
641 |
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
6274de498
|
642 643 |
if (kprobe_disabled(&op->kp)) arch_disarm_kprobe(&op->kp); |
afd66255b
|
644 645 646 |
} /* Unoptimize a kprobe if p is optimized */ |
55479f647
|
647 |
static void unoptimize_kprobe(struct kprobe *p, bool force) |
afd66255b
|
648 649 |
{ struct optimized_kprobe *op; |
6274de498
|
650 651 652 653 |
if (!kprobe_aggrprobe(p) || kprobe_disarmed(p)) return; /* This is not an optprobe nor optimized */ op = container_of(p, struct optimized_kprobe, kp); |
4771b3f60
|
654 |
if (!kprobe_optimized(p)) |
6274de498
|
655 |
return; |
6274de498
|
656 |
|
6274de498
|
657 |
if (!list_empty(&op->list)) { |
4771b3f60
|
658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 |
if (optprobe_queued_unopt(op)) { /* Queued in unoptimizing queue */ if (force) { /* * Forcibly unoptimize the kprobe here, and queue it * in the freeing list for release afterwards. */ force_unoptimize_kprobe(op); list_move(&op->list, &freeing_list); } } else { /* Dequeue from the optimizing queue */ list_del_init(&op->list); op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; } |
6274de498
|
673 674 |
return; } |
4771b3f60
|
675 |
|
6274de498
|
676 |
/* Optimized kprobe case */ |
4771b3f60
|
677 |
if (force) { |
6274de498
|
678 679 |
/* Forcibly update the code: this is a special case */ force_unoptimize_kprobe(op); |
4771b3f60
|
680 |
} else { |
6274de498
|
681 682 |
list_add(&op->list, &unoptimizing_list); kick_kprobe_optimizer(); |
afd66255b
|
683 684 |
} } |
0490cd1f9
|
685 |
/* Cancel unoptimizing for reusing */ |
819319fc9
|
686 |
static int reuse_unused_kprobe(struct kprobe *ap) |
0490cd1f9
|
687 688 |
{ struct optimized_kprobe *op; |
0490cd1f9
|
689 690 691 692 693 |
/* * Unused kprobe MUST be on the way of delayed unoptimizing (means * there is still a relative jump) and disabled. */ op = container_of(ap, struct optimized_kprobe, kp); |
4458515b2
|
694 |
WARN_ON_ONCE(list_empty(&op->list)); |
0490cd1f9
|
695 696 697 |
/* Enable the probe again */ ap->flags &= ~KPROBE_FLAG_DISABLED; /* Optimize it again (remove from op->list) */ |
5f843ed41
|
698 699 |
if (!kprobe_optready(ap)) return -EINVAL; |
819319fc9
|
700 |
|
0490cd1f9
|
701 |
optimize_kprobe(ap); |
819319fc9
|
702 |
return 0; |
0490cd1f9
|
703 |
} |
afd66255b
|
704 |
/* Remove optimized instructions */ |
55479f647
|
705 |
static void kill_optimized_kprobe(struct kprobe *p) |
afd66255b
|
706 707 708 709 |
{ struct optimized_kprobe *op; op = container_of(p, struct optimized_kprobe, kp); |
6274de498
|
710 711 |
if (!list_empty(&op->list)) /* Dequeue from the (un)optimization queue */ |
afd66255b
|
712 |
list_del_init(&op->list); |
6274de498
|
713 |
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; |
7b959fc58
|
714 715 716 717 718 719 720 721 722 723 724 |
if (kprobe_unused(p)) { /* Enqueue if it is unused */ list_add(&op->list, &freeing_list); /* * Remove unused probes from the hash list. After waiting * for synchronization, this probe is reclaimed. * (reclaiming is done by do_free_cleaned_kprobes().) */ hlist_del_rcu(&op->kp.hlist); } |
6274de498
|
725 |
/* Don't touch the code, because it is already freed. */ |
afd66255b
|
726 727 |
arch_remove_optimized_kprobe(op); } |
a460246c7
|
728 729 730 731 732 733 |
static inline void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) { if (!kprobe_ftrace(p)) arch_prepare_optimized_kprobe(op, p); } |
afd66255b
|
734 |
/* Try to prepare optimized instructions */ |
55479f647
|
735 |
static void prepare_optimized_kprobe(struct kprobe *p) |
afd66255b
|
736 737 738 739 |
{ struct optimized_kprobe *op; op = container_of(p, struct optimized_kprobe, kp); |
a460246c7
|
740 |
__prepare_optimized_kprobe(op, p); |
afd66255b
|
741 |
} |
afd66255b
|
742 |
/* Allocate new optimized_kprobe and try to prepare optimized instructions */ |
55479f647
|
743 |
static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255b
|
744 745 746 747 748 749 750 751 752 |
{ struct optimized_kprobe *op; op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL); if (!op) return NULL; INIT_LIST_HEAD(&op->list); op->kp.addr = p->addr; |
a460246c7
|
753 |
__prepare_optimized_kprobe(op, p); |
afd66255b
|
754 755 756 |
return &op->kp; } |
55479f647
|
757 |
static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p); |
afd66255b
|
758 759 760 761 762 |
/* * Prepare an optimized_kprobe and optimize it * NOTE: p must be a normal registered kprobe */ |
55479f647
|
763 |
static void try_to_optimize_kprobe(struct kprobe *p) |
afd66255b
|
764 765 766 |
{ struct kprobe *ap; struct optimized_kprobe *op; |
ae6aa16fd
|
767 768 769 |
/* Impossible to optimize ftrace-based kprobe */ if (kprobe_ftrace(p)) return; |
25764288d
|
770 |
/* For preparing optimization, jump_label_text_reserved() is called */ |
2d1e38f56
|
771 |
cpus_read_lock(); |
25764288d
|
772 773 |
jump_label_lock(); mutex_lock(&text_mutex); |
afd66255b
|
774 775 |
ap = alloc_aggr_kprobe(p); if (!ap) |
25764288d
|
776 |
goto out; |
afd66255b
|
777 778 779 780 |
op = container_of(ap, struct optimized_kprobe, kp); if (!arch_prepared_optinsn(&op->optinsn)) { /* If failed to setup optimizing, fallback to kprobe */ |
6274de498
|
781 782 |
arch_remove_optimized_kprobe(op); kfree(op); |
25764288d
|
783 |
goto out; |
afd66255b
|
784 785 786 |
} init_aggr_kprobe(ap, p); |
25764288d
|
787 788 789 790 791 |
optimize_kprobe(ap); /* This just kicks optimizer thread */ out: mutex_unlock(&text_mutex); jump_label_unlock(); |
2d1e38f56
|
792 |
cpus_read_unlock(); |
afd66255b
|
793 |
} |
b2be84df9
|
794 |
#ifdef CONFIG_SYSCTL |
55479f647
|
795 |
static void optimize_all_kprobes(void) |
b2be84df9
|
796 797 |
{ struct hlist_head *head; |
b2be84df9
|
798 799 |
struct kprobe *p; unsigned int i; |
5c51543b0
|
800 |
mutex_lock(&kprobe_mutex); |
b2be84df9
|
801 802 |
/* If optimization is already allowed, just return */ if (kprobes_allow_optimization) |
5c51543b0
|
803 |
goto out; |
b2be84df9
|
804 |
|
2d1e38f56
|
805 |
cpus_read_lock(); |
b2be84df9
|
806 |
kprobes_allow_optimization = true; |
b2be84df9
|
807 808 |
for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; |
b67bfe0d4
|
809 |
hlist_for_each_entry_rcu(p, head, hlist) |
b2be84df9
|
810 811 812 |
if (!kprobe_disabled(p)) optimize_kprobe(p); } |
2d1e38f56
|
813 |
cpus_read_unlock(); |
b2be84df9
|
814 815 |
printk(KERN_INFO "Kprobes globally optimized "); |
5c51543b0
|
816 817 |
out: mutex_unlock(&kprobe_mutex); |
b2be84df9
|
818 |
} |
55479f647
|
819 |
static void unoptimize_all_kprobes(void) |
b2be84df9
|
820 821 |
{ struct hlist_head *head; |
b2be84df9
|
822 823 |
struct kprobe *p; unsigned int i; |
5c51543b0
|
824 |
mutex_lock(&kprobe_mutex); |
b2be84df9
|
825 |
/* If optimization is already prohibited, just return */ |
5c51543b0
|
826 827 |
if (!kprobes_allow_optimization) { mutex_unlock(&kprobe_mutex); |
b2be84df9
|
828 |
return; |
5c51543b0
|
829 |
} |
b2be84df9
|
830 |
|
2d1e38f56
|
831 |
cpus_read_lock(); |
b2be84df9
|
832 |
kprobes_allow_optimization = false; |
b2be84df9
|
833 834 |
for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; |
b67bfe0d4
|
835 |
hlist_for_each_entry_rcu(p, head, hlist) { |
b2be84df9
|
836 |
if (!kprobe_disabled(p)) |
6274de498
|
837 |
unoptimize_kprobe(p, false); |
b2be84df9
|
838 839 |
} } |
2d1e38f56
|
840 |
cpus_read_unlock(); |
5c51543b0
|
841 |
mutex_unlock(&kprobe_mutex); |
6274de498
|
842 843 844 845 |
/* Wait for unoptimizing completion */ wait_for_kprobe_optimizer(); printk(KERN_INFO "Kprobes globally unoptimized "); |
b2be84df9
|
846 |
} |
5c51543b0
|
847 |
static DEFINE_MUTEX(kprobe_sysctl_mutex); |
b2be84df9
|
848 849 850 851 852 853 |
int sysctl_kprobes_optimization; int proc_kprobes_optimization_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { int ret; |
5c51543b0
|
854 |
mutex_lock(&kprobe_sysctl_mutex); |
b2be84df9
|
855 856 857 858 859 860 861 |
sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0; ret = proc_dointvec_minmax(table, write, buffer, length, ppos); if (sysctl_kprobes_optimization) optimize_all_kprobes(); else unoptimize_all_kprobes(); |
5c51543b0
|
862 |
mutex_unlock(&kprobe_sysctl_mutex); |
b2be84df9
|
863 864 865 866 |
return ret; } #endif /* CONFIG_SYSCTL */ |
6274de498
|
867 |
/* Put a breakpoint for a probe. Must be called with text_mutex locked */ |
55479f647
|
868 |
static void __arm_kprobe(struct kprobe *p) |
afd66255b
|
869 |
{ |
6d8e40a85
|
870 |
struct kprobe *_p; |
afd66255b
|
871 872 |
/* Check collision with other optimized kprobes */ |
6d8e40a85
|
873 874 |
_p = get_optimized_kprobe((unsigned long)p->addr); if (unlikely(_p)) |
6274de498
|
875 876 |
/* Fallback to unoptimized kprobe */ unoptimize_kprobe(_p, true); |
afd66255b
|
877 878 879 880 |
arch_arm_kprobe(p); optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */ } |
6274de498
|
881 |
/* Remove the breakpoint of a probe. Must be called with text_mutex locked */ |
55479f647
|
882 |
static void __disarm_kprobe(struct kprobe *p, bool reopt) |
afd66255b
|
883 |
{ |
6d8e40a85
|
884 |
struct kprobe *_p; |
afd66255b
|
885 |
|
69d54b916
|
886 887 |
/* Try to unoptimize */ unoptimize_kprobe(p, kprobes_all_disarmed); |
afd66255b
|
888 |
|
6274de498
|
889 890 891 892 893 894 895 896 |
if (!kprobe_queued(p)) { arch_disarm_kprobe(p); /* If another kprobe was blocked, optimize it. */ _p = get_optimized_kprobe((unsigned long)p->addr); if (unlikely(_p) && reopt) optimize_kprobe(_p); } /* TODO: reoptimize others after unoptimized this probe */ |
afd66255b
|
897 898 899 900 901 |
} #else /* !CONFIG_OPTPROBES */ #define optimize_kprobe(p) do {} while (0) |
6274de498
|
902 |
#define unoptimize_kprobe(p, f) do {} while (0) |
afd66255b
|
903 904 905 906 |
#define kill_optimized_kprobe(p) do {} while (0) #define prepare_optimized_kprobe(p) do {} while (0) #define try_to_optimize_kprobe(p) do {} while (0) #define __arm_kprobe(p) arch_arm_kprobe(p) |
6274de498
|
907 908 909 |
#define __disarm_kprobe(p, o) arch_disarm_kprobe(p) #define kprobe_disarmed(p) kprobe_disabled(p) #define wait_for_kprobe_optimizer() do {} while (0) |
afd66255b
|
910 |
|
819319fc9
|
911 |
static int reuse_unused_kprobe(struct kprobe *ap) |
0490cd1f9
|
912 |
{ |
819319fc9
|
913 914 915 916 917 918 |
/* * If the optimized kprobe is NOT supported, the aggr kprobe is * released at the same time that the last aggregated kprobe is * unregistered. * Thus there should be no chance to reuse unused kprobe. */ |
0490cd1f9
|
919 920 |
printk(KERN_ERR "Error: There should be no unused kprobe here. "); |
819319fc9
|
921 |
return -EINVAL; |
0490cd1f9
|
922 |
} |
55479f647
|
923 |
static void free_aggr_kprobe(struct kprobe *p) |
afd66255b
|
924 |
{ |
6274de498
|
925 |
arch_remove_kprobe(p); |
afd66255b
|
926 927 |
kfree(p); } |
55479f647
|
928 |
static struct kprobe *alloc_aggr_kprobe(struct kprobe *p) |
afd66255b
|
929 930 931 932 |
{ return kzalloc(sizeof(struct kprobe), GFP_KERNEL); } #endif /* CONFIG_OPTPROBES */ |
e7dbfe349
|
933 |
#ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16fd
|
934 |
static struct ftrace_ops kprobe_ftrace_ops __read_mostly = { |
e52538965
|
935 |
.func = kprobe_ftrace_handler, |
0bc11ed5a
|
936 937 938 939 940 |
.flags = FTRACE_OPS_FL_SAVE_REGS, }; static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = { .func = kprobe_ftrace_handler, |
1d70be34d
|
941 |
.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY, |
ae6aa16fd
|
942 |
}; |
0bc11ed5a
|
943 944 |
static int kprobe_ipmodify_enabled; |
ae6aa16fd
|
945 946 947 |
static int kprobe_ftrace_enabled; /* Must ensure p->addr is really on ftrace */ |
55479f647
|
948 |
static int prepare_kprobe(struct kprobe *p) |
ae6aa16fd
|
949 950 951 952 953 954 955 956 |
{ if (!kprobe_ftrace(p)) return arch_prepare_kprobe(p); return arch_prepare_kprobe_ftrace(p); } /* Caller must lock kprobe_mutex */ |
0bc11ed5a
|
957 958 |
static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, int *cnt) |
ae6aa16fd
|
959 |
{ |
12310e343
|
960 |
int ret = 0; |
ae6aa16fd
|
961 |
|
0bc11ed5a
|
962 |
ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0); |
12310e343
|
963 |
if (ret) { |
4458515b2
|
964 965 966 |
pr_debug("Failed to arm kprobe-ftrace at %pS (%d) ", p->addr, ret); |
12310e343
|
967 968 |
return ret; } |
0bc11ed5a
|
969 970 |
if (*cnt == 0) { ret = register_ftrace_function(ops); |
12310e343
|
971 972 973 974 975 |
if (ret) { pr_debug("Failed to init kprobe-ftrace (%d) ", ret); goto err_ftrace; } |
ae6aa16fd
|
976 |
} |
12310e343
|
977 |
|
0bc11ed5a
|
978 |
(*cnt)++; |
12310e343
|
979 980 981 982 |
return ret; err_ftrace: /* |
0bc11ed5a
|
983 984 |
* At this point, sinec ops is not registered, we should be sefe from * registering empty filter. |
12310e343
|
985 |
*/ |
0bc11ed5a
|
986 |
ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
12310e343
|
987 |
return ret; |
ae6aa16fd
|
988 |
} |
0bc11ed5a
|
989 990 991 992 993 994 995 996 |
static int arm_kprobe_ftrace(struct kprobe *p) { bool ipmodify = (p->post_handler != NULL); return __arm_kprobe_ftrace(p, ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); } |
ae6aa16fd
|
997 |
/* Caller must lock kprobe_mutex */ |
0bc11ed5a
|
998 999 |
static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, int *cnt) |
ae6aa16fd
|
1000 |
{ |
297f9233b
|
1001 |
int ret = 0; |
ae6aa16fd
|
1002 |
|
0bc11ed5a
|
1003 1004 |
if (*cnt == 1) { ret = unregister_ftrace_function(ops); |
297f9233b
|
1005 1006 1007 |
if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d) ", ret)) return ret; |
ae6aa16fd
|
1008 |
} |
297f9233b
|
1009 |
|
0bc11ed5a
|
1010 |
(*cnt)--; |
297f9233b
|
1011 |
|
0bc11ed5a
|
1012 |
ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); |
4458515b2
|
1013 1014 1015 |
WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d) ", p->addr, ret); |
297f9233b
|
1016 |
return ret; |
ae6aa16fd
|
1017 |
} |
0bc11ed5a
|
1018 1019 1020 1021 1022 1023 1024 1025 1026 |
static int disarm_kprobe_ftrace(struct kprobe *p) { bool ipmodify = (p->post_handler != NULL); return __disarm_kprobe_ftrace(p, ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops, ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled); } |
e7dbfe349
|
1027 |
#else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16fd
|
1028 |
#define prepare_kprobe(p) arch_prepare_kprobe(p) |
12310e343
|
1029 |
#define arm_kprobe_ftrace(p) (-ENODEV) |
297f9233b
|
1030 |
#define disarm_kprobe_ftrace(p) (-ENODEV) |
ae6aa16fd
|
1031 |
#endif |
201517a7f
|
1032 |
/* Arm a kprobe with text_mutex */ |
12310e343
|
1033 |
static int arm_kprobe(struct kprobe *kp) |
201517a7f
|
1034 |
{ |
12310e343
|
1035 1036 |
if (unlikely(kprobe_ftrace(kp))) return arm_kprobe_ftrace(kp); |
2d1e38f56
|
1037 |
cpus_read_lock(); |
201517a7f
|
1038 |
mutex_lock(&text_mutex); |
afd66255b
|
1039 |
__arm_kprobe(kp); |
201517a7f
|
1040 |
mutex_unlock(&text_mutex); |
2d1e38f56
|
1041 |
cpus_read_unlock(); |
12310e343
|
1042 1043 |
return 0; |
201517a7f
|
1044 1045 1046 |
} /* Disarm a kprobe with text_mutex */ |
297f9233b
|
1047 |
static int disarm_kprobe(struct kprobe *kp, bool reopt) |
201517a7f
|
1048 |
{ |
297f9233b
|
1049 1050 |
if (unlikely(kprobe_ftrace(kp))) return disarm_kprobe_ftrace(kp); |
2d1e38f56
|
1051 1052 |
cpus_read_lock(); |
201517a7f
|
1053 |
mutex_lock(&text_mutex); |
ae6aa16fd
|
1054 |
__disarm_kprobe(kp, reopt); |
201517a7f
|
1055 |
mutex_unlock(&text_mutex); |
2d1e38f56
|
1056 |
cpus_read_unlock(); |
297f9233b
|
1057 1058 |
return 0; |
201517a7f
|
1059 |
} |
64f562c6d
|
1060 1061 1062 1063 |
/* * Aggregate handlers for multiple kprobes support - these handlers * take care of invoking the individual kprobe handlers on p->list */ |
820aede02
|
1064 |
static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs) |
64f562c6d
|
1065 1066 |
{ struct kprobe *kp; |
3516a4604
|
1067 |
list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d5
|
1068 |
if (kp->pre_handler && likely(!kprobe_disabled(kp))) { |
e65845235
|
1069 |
set_kprobe_instance(kp); |
8b0914ea7
|
1070 1071 |
if (kp->pre_handler(kp, regs)) return 1; |
64f562c6d
|
1072 |
} |
e65845235
|
1073 |
reset_kprobe_instance(); |
64f562c6d
|
1074 1075 1076 |
} return 0; } |
820aede02
|
1077 |
NOKPROBE_SYMBOL(aggr_pre_handler); |
64f562c6d
|
1078 |
|
820aede02
|
1079 1080 |
static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs, unsigned long flags) |
64f562c6d
|
1081 1082 |
{ struct kprobe *kp; |
3516a4604
|
1083 |
list_for_each_entry_rcu(kp, &p->list, list) { |
de5bd88d5
|
1084 |
if (kp->post_handler && likely(!kprobe_disabled(kp))) { |
e65845235
|
1085 |
set_kprobe_instance(kp); |
64f562c6d
|
1086 |
kp->post_handler(kp, regs, flags); |
e65845235
|
1087 |
reset_kprobe_instance(); |
64f562c6d
|
1088 1089 |
} } |
64f562c6d
|
1090 |
} |
820aede02
|
1091 |
NOKPROBE_SYMBOL(aggr_post_handler); |
64f562c6d
|
1092 |
|
820aede02
|
1093 1094 |
static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs, int trapnr) |
64f562c6d
|
1095 |
{ |
b76834bc1
|
1096 |
struct kprobe *cur = __this_cpu_read(kprobe_instance); |
e65845235
|
1097 |
|
64f562c6d
|
1098 1099 1100 1101 |
/* * if we faulted "during" the execution of a user specified * probe handler, invoke just that probe's fault handler */ |
e65845235
|
1102 1103 |
if (cur && cur->fault_handler) { if (cur->fault_handler(cur, regs, trapnr)) |
64f562c6d
|
1104 1105 1106 1107 |
return 1; } return 0; } |
820aede02
|
1108 |
NOKPROBE_SYMBOL(aggr_fault_handler); |
64f562c6d
|
1109 |
|
bf8d5c52c
|
1110 |
/* Walks the list and increments nmissed count for multiprobe case */ |
820aede02
|
1111 |
void kprobes_inc_nmissed_count(struct kprobe *p) |
bf8d5c52c
|
1112 1113 |
{ struct kprobe *kp; |
afd66255b
|
1114 |
if (!kprobe_aggrprobe(p)) { |
bf8d5c52c
|
1115 1116 1117 1118 1119 1120 1121 |
p->nmissed++; } else { list_for_each_entry_rcu(kp, &p->list, list) kp->nmissed++; } return; } |
820aede02
|
1122 |
NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); |
bf8d5c52c
|
1123 |
|
820aede02
|
1124 1125 |
void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head) |
b94cce926
|
1126 |
{ |
ef53d9c5e
|
1127 |
struct kretprobe *rp = ri->rp; |
b94cce926
|
1128 1129 |
/* remove rp inst off the rprobe_inst_table */ hlist_del(&ri->hlist); |
ef53d9c5e
|
1130 1131 |
INIT_HLIST_NODE(&ri->hlist); if (likely(rp)) { |
ec484608c
|
1132 |
raw_spin_lock(&rp->lock); |
ef53d9c5e
|
1133 |
hlist_add_head(&ri->hlist, &rp->free_instances); |
ec484608c
|
1134 |
raw_spin_unlock(&rp->lock); |
b94cce926
|
1135 1136 |
} else /* Unregistering */ |
99219a3fb
|
1137 |
hlist_add_head(&ri->hlist, head); |
b94cce926
|
1138 |
} |
820aede02
|
1139 |
NOKPROBE_SYMBOL(recycle_rp_inst); |
b94cce926
|
1140 |
|
820aede02
|
1141 |
void kretprobe_hash_lock(struct task_struct *tsk, |
ef53d9c5e
|
1142 |
struct hlist_head **head, unsigned long *flags) |
635c17c2b
|
1143 |
__acquires(hlist_lock) |
ef53d9c5e
|
1144 1145 |
{ unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
ec484608c
|
1146 |
raw_spinlock_t *hlist_lock; |
ef53d9c5e
|
1147 1148 1149 |
*head = &kretprobe_inst_table[hash]; hlist_lock = kretprobe_table_lock_ptr(hash); |
ec484608c
|
1150 |
raw_spin_lock_irqsave(hlist_lock, *flags); |
ef53d9c5e
|
1151 |
} |
820aede02
|
1152 |
NOKPROBE_SYMBOL(kretprobe_hash_lock); |
ef53d9c5e
|
1153 |
|
820aede02
|
1154 1155 |
static void kretprobe_table_lock(unsigned long hash, unsigned long *flags) |
635c17c2b
|
1156 |
__acquires(hlist_lock) |
b94cce926
|
1157 |
{ |
ec484608c
|
1158 1159 |
raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); raw_spin_lock_irqsave(hlist_lock, *flags); |
ef53d9c5e
|
1160 |
} |
820aede02
|
1161 |
NOKPROBE_SYMBOL(kretprobe_table_lock); |
ef53d9c5e
|
1162 |
|
820aede02
|
1163 1164 |
void kretprobe_hash_unlock(struct task_struct *tsk, unsigned long *flags) |
635c17c2b
|
1165 |
__releases(hlist_lock) |
ef53d9c5e
|
1166 1167 |
{ unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS); |
ec484608c
|
1168 |
raw_spinlock_t *hlist_lock; |
ef53d9c5e
|
1169 1170 |
hlist_lock = kretprobe_table_lock_ptr(hash); |
ec484608c
|
1171 |
raw_spin_unlock_irqrestore(hlist_lock, *flags); |
ef53d9c5e
|
1172 |
} |
820aede02
|
1173 |
NOKPROBE_SYMBOL(kretprobe_hash_unlock); |
ef53d9c5e
|
1174 |
|
820aede02
|
1175 1176 |
static void kretprobe_table_unlock(unsigned long hash, unsigned long *flags) |
635c17c2b
|
1177 |
__releases(hlist_lock) |
ef53d9c5e
|
1178 |
{ |
ec484608c
|
1179 1180 |
raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash); raw_spin_unlock_irqrestore(hlist_lock, *flags); |
b94cce926
|
1181 |
} |
820aede02
|
1182 |
NOKPROBE_SYMBOL(kretprobe_table_unlock); |
b94cce926
|
1183 |
|
3d390370d
|
1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 |
struct kprobe kprobe_busy = { .addr = (void *) get_kprobe, }; void kprobe_busy_begin(void) { struct kprobe_ctlblk *kcb; preempt_disable(); __this_cpu_write(current_kprobe, &kprobe_busy); kcb = get_kprobe_ctlblk(); kcb->kprobe_status = KPROBE_HIT_ACTIVE; } void kprobe_busy_end(void) { __this_cpu_write(current_kprobe, NULL); preempt_enable(); } |
b94cce926
|
1203 |
/* |
c6fd91f0b
|
1204 1205 1206 1207 |
* This function is called from finish_task_switch when task tk becomes dead, * so that we can recycle any function-return probe instances associated * with this task. These left over instances represent probed functions * that have been called but will never return. |
b94cce926
|
1208 |
*/ |
820aede02
|
1209 |
void kprobe_flush_task(struct task_struct *tk) |
b94cce926
|
1210 |
{ |
62c27be0d
|
1211 |
struct kretprobe_instance *ri; |
99219a3fb
|
1212 |
struct hlist_head *head, empty_rp; |
b67bfe0d4
|
1213 |
struct hlist_node *tmp; |
ef53d9c5e
|
1214 |
unsigned long hash, flags = 0; |
802eae7c8
|
1215 |
|
ef53d9c5e
|
1216 1217 1218 |
if (unlikely(!kprobes_initialized)) /* Early boot. kretprobe_table_locks not yet initialized. */ return; |
3d390370d
|
1219 |
kprobe_busy_begin(); |
d496aab56
|
1220 |
INIT_HLIST_HEAD(&empty_rp); |
ef53d9c5e
|
1221 1222 1223 |
hash = hash_ptr(tk, KPROBE_HASH_BITS); head = &kretprobe_inst_table[hash]; kretprobe_table_lock(hash, &flags); |
b67bfe0d4
|
1224 |
hlist_for_each_entry_safe(ri, tmp, head, hlist) { |
62c27be0d
|
1225 |
if (ri->task == tk) |
99219a3fb
|
1226 |
recycle_rp_inst(ri, &empty_rp); |
62c27be0d
|
1227 |
} |
ef53d9c5e
|
1228 |
kretprobe_table_unlock(hash, &flags); |
b67bfe0d4
|
1229 |
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |
99219a3fb
|
1230 1231 1232 |
hlist_del(&ri->hlist); kfree(ri); } |
3d390370d
|
1233 1234 |
kprobe_busy_end(); |
b94cce926
|
1235 |
} |
820aede02
|
1236 |
NOKPROBE_SYMBOL(kprobe_flush_task); |
b94cce926
|
1237 |
|
b94cce926
|
1238 1239 1240 |
static inline void free_rp_inst(struct kretprobe *rp) { struct kretprobe_instance *ri; |
b67bfe0d4
|
1241 |
struct hlist_node *next; |
4c4308cb9
|
1242 |
|
b67bfe0d4
|
1243 |
hlist_for_each_entry_safe(ri, next, &rp->free_instances, hlist) { |
ef53d9c5e
|
1244 |
hlist_del(&ri->hlist); |
b94cce926
|
1245 1246 1247 |
kfree(ri); } } |
820aede02
|
1248 |
static void cleanup_rp_inst(struct kretprobe *rp) |
4a296e07c
|
1249 |
{ |
ef53d9c5e
|
1250 |
unsigned long flags, hash; |
4a296e07c
|
1251 |
struct kretprobe_instance *ri; |
b67bfe0d4
|
1252 |
struct hlist_node *next; |
ef53d9c5e
|
1253 |
struct hlist_head *head; |
4a296e07c
|
1254 |
/* No race here */ |
ef53d9c5e
|
1255 1256 1257 |
for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) { kretprobe_table_lock(hash, &flags); head = &kretprobe_inst_table[hash]; |
b67bfe0d4
|
1258 |
hlist_for_each_entry_safe(ri, next, head, hlist) { |
ef53d9c5e
|
1259 1260 1261 1262 |
if (ri->rp == rp) ri->rp = NULL; } kretprobe_table_unlock(hash, &flags); |
4a296e07c
|
1263 |
} |
4a296e07c
|
1264 1265 |
free_rp_inst(rp); } |
820aede02
|
1266 |
NOKPROBE_SYMBOL(cleanup_rp_inst); |
4a296e07c
|
1267 |
|
059053a27
|
1268 |
/* Add the new probe to ap->list */ |
55479f647
|
1269 |
static int add_new_kprobe(struct kprobe *ap, struct kprobe *p) |
8b0914ea7
|
1270 |
{ |
059053a27
|
1271 |
if (p->post_handler) |
6274de498
|
1272 |
unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */ |
afd66255b
|
1273 |
|
059053a27
|
1274 |
list_add_rcu(&p->list, &ap->list); |
b918e5e60
|
1275 1276 |
if (p->post_handler && !ap->post_handler) ap->post_handler = aggr_post_handler; |
de5bd88d5
|
1277 |
|
8b0914ea7
|
1278 1279 1280 1281 |
return 0; } /* |
64f562c6d
|
1282 1283 1284 |
* Fill in the required fields of the "manager kprobe". Replace the * earlier kprobe in the hlist with the manager kprobe */ |
55479f647
|
1285 |
static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p) |
64f562c6d
|
1286 |
{ |
afd66255b
|
1287 |
/* Copy p's insn slot to ap */ |
8b0914ea7
|
1288 |
copy_kprobe(p, ap); |
a9ad965ea
|
1289 |
flush_insn_slot(ap); |
64f562c6d
|
1290 |
ap->addr = p->addr; |
afd66255b
|
1291 |
ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED; |
64f562c6d
|
1292 |
ap->pre_handler = aggr_pre_handler; |
64f562c6d
|
1293 |
ap->fault_handler = aggr_fault_handler; |
e8386a0cb
|
1294 1295 |
/* We don't care the kprobe which has gone. */ if (p->post_handler && !kprobe_gone(p)) |
367216567
|
1296 |
ap->post_handler = aggr_post_handler; |
64f562c6d
|
1297 1298 |
INIT_LIST_HEAD(&ap->list); |
afd66255b
|
1299 |
INIT_HLIST_NODE(&ap->hlist); |
64f562c6d
|
1300 |
|
afd66255b
|
1301 |
list_add_rcu(&p->list, &ap->list); |
adad0f331
|
1302 |
hlist_replace_rcu(&p->hlist, &ap->hlist); |
64f562c6d
|
1303 1304 1305 1306 1307 |
} /* * This is the second or subsequent kprobe at the address - handle * the intricacies |
64f562c6d
|
1308 |
*/ |
55479f647
|
1309 |
static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) |
64f562c6d
|
1310 1311 |
{ int ret = 0; |
6d8e40a85
|
1312 |
struct kprobe *ap = orig_p; |
64f562c6d
|
1313 |
|
2d1e38f56
|
1314 |
cpus_read_lock(); |
25764288d
|
1315 1316 |
/* For preparing optimization, jump_label_text_reserved() is called */ jump_label_lock(); |
25764288d
|
1317 |
mutex_lock(&text_mutex); |
6d8e40a85
|
1318 1319 1320 |
if (!kprobe_aggrprobe(orig_p)) { /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */ ap = alloc_aggr_kprobe(orig_p); |
25764288d
|
1321 1322 1323 1324 |
if (!ap) { ret = -ENOMEM; goto out; } |
6d8e40a85
|
1325 |
init_aggr_kprobe(ap, orig_p); |
819319fc9
|
1326 |
} else if (kprobe_unused(ap)) { |
0490cd1f9
|
1327 |
/* This probe is going to die. Rescue it */ |
819319fc9
|
1328 1329 1330 1331 |
ret = reuse_unused_kprobe(ap); if (ret) goto out; } |
b918e5e60
|
1332 1333 |
if (kprobe_gone(ap)) { |
e8386a0cb
|
1334 1335 1336 1337 1338 1339 |
/* * Attempting to insert new probe at the same location that * had a probe in the module vaddr area which already * freed. So, the instruction slot has already been * released. We need a new slot for the new probe. */ |
b918e5e60
|
1340 |
ret = arch_prepare_kprobe(ap); |
e8386a0cb
|
1341 |
if (ret) |
b918e5e60
|
1342 1343 1344 1345 1346 |
/* * Even if fail to allocate new slot, don't need to * free aggr_probe. It will be used next time, or * freed by unregister_kprobe. */ |
25764288d
|
1347 |
goto out; |
de5bd88d5
|
1348 |
|
afd66255b
|
1349 1350 |
/* Prepare optimized instructions if possible. */ prepare_optimized_kprobe(ap); |
e8386a0cb
|
1351 |
/* |
de5bd88d5
|
1352 1353 |
* Clear gone flag to prevent allocating new slot again, and * set disabled flag because it is not armed yet. |
e8386a0cb
|
1354 |
*/ |
de5bd88d5
|
1355 1356 |
ap->flags = (ap->flags & ~KPROBE_FLAG_GONE) | KPROBE_FLAG_DISABLED; |
e8386a0cb
|
1357 |
} |
b918e5e60
|
1358 |
|
afd66255b
|
1359 |
/* Copy ap's insn slot to p */ |
b918e5e60
|
1360 |
copy_kprobe(ap, p); |
25764288d
|
1361 1362 1363 1364 |
ret = add_new_kprobe(ap, p); out: mutex_unlock(&text_mutex); |
25764288d
|
1365 |
jump_label_unlock(); |
2d1e38f56
|
1366 |
cpus_read_unlock(); |
25764288d
|
1367 1368 1369 |
if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { ap->flags &= ~KPROBE_FLAG_DISABLED; |
12310e343
|
1370 |
if (!kprobes_all_disarmed) { |
25764288d
|
1371 |
/* Arm the breakpoint again. */ |
12310e343
|
1372 1373 1374 1375 |
ret = arm_kprobe(ap); if (ret) { ap->flags |= KPROBE_FLAG_DISABLED; list_del_rcu(&p->list); |
ae8b7ce76
|
1376 |
synchronize_rcu(); |
12310e343
|
1377 1378 |
} } |
25764288d
|
1379 1380 |
} return ret; |
64f562c6d
|
1381 |
} |
be8f27432
|
1382 1383 1384 1385 1386 1387 |
bool __weak arch_within_kprobe_blacklist(unsigned long addr) { /* The __kprobes marked functions and entry code must not be probed */ return addr >= (unsigned long)__kprobes_text_start && addr < (unsigned long)__kprobes_text_end; } |
6143c6fb1
|
1388 |
static bool __within_kprobe_blacklist(unsigned long addr) |
d0aaff979
|
1389 |
{ |
376e24242
|
1390 |
struct kprobe_blacklist_entry *ent; |
3d8d996e0
|
1391 |
|
be8f27432
|
1392 |
if (arch_within_kprobe_blacklist(addr)) |
376e24242
|
1393 |
return true; |
3d8d996e0
|
1394 1395 1396 1397 |
/* * If there exists a kprobe_blacklist, verify and * fail any probe registration in the prohibited area */ |
376e24242
|
1398 1399 1400 |
list_for_each_entry(ent, &kprobe_blacklist, list) { if (addr >= ent->start_addr && addr < ent->end_addr) return true; |
3d8d996e0
|
1401 |
} |
6143c6fb1
|
1402 1403 |
return false; } |
376e24242
|
1404 |
|
6143c6fb1
|
1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 |
bool within_kprobe_blacklist(unsigned long addr) { char symname[KSYM_NAME_LEN], *p; if (__within_kprobe_blacklist(addr)) return true; /* Check if the address is on a suffixed-symbol */ if (!lookup_symbol_name(addr, symname)) { p = strchr(symname, '.'); if (!p) return false; *p = '\0'; addr = (unsigned long)kprobe_lookup_name(symname, 0); if (addr) return __within_kprobe_blacklist(addr); } |
376e24242
|
1422 |
return false; |
d0aaff979
|
1423 |
} |
b2a5cd693
|
1424 1425 1426 |
/* * If we have a symbol_name argument, look it up and add the offset field * to it. This way, we can specify a relative address to a symbol. |
bc81d48d1
|
1427 1428 |
* This returns encoded errors if it fails to look up symbol or invalid * combination of parameters. |
b2a5cd693
|
1429 |
*/ |
1d585e709
|
1430 1431 |
static kprobe_opcode_t *_kprobe_addr(kprobe_opcode_t *addr, const char *symbol_name, unsigned int offset) |
b2a5cd693
|
1432 |
{ |
1d585e709
|
1433 |
if ((symbol_name && addr) || (!symbol_name && !addr)) |
bc81d48d1
|
1434 |
goto invalid; |
1d585e709
|
1435 |
if (symbol_name) { |
7246f6006
|
1436 |
addr = kprobe_lookup_name(symbol_name, offset); |
bc81d48d1
|
1437 1438 |
if (!addr) return ERR_PTR(-ENOENT); |
b2a5cd693
|
1439 |
} |
1d585e709
|
1440 |
addr = (kprobe_opcode_t *)(((char *)addr) + offset); |
bc81d48d1
|
1441 1442 1443 1444 1445 |
if (addr) return addr; invalid: return ERR_PTR(-EINVAL); |
b2a5cd693
|
1446 |
} |
1d585e709
|
1447 1448 1449 1450 |
static kprobe_opcode_t *kprobe_addr(struct kprobe *p) { return _kprobe_addr(p->addr, p->symbol_name, p->offset); } |
1f0ab4097
|
1451 |
/* Check passed kprobe is valid and return kprobe in kprobe_table. */ |
55479f647
|
1452 |
static struct kprobe *__get_valid_kprobe(struct kprobe *p) |
1f0ab4097
|
1453 |
{ |
6d8e40a85
|
1454 |
struct kprobe *ap, *list_p; |
1f0ab4097
|
1455 |
|
6d8e40a85
|
1456 1457 |
ap = get_kprobe(p->addr); if (unlikely(!ap)) |
1f0ab4097
|
1458 |
return NULL; |
6d8e40a85
|
1459 1460 |
if (p != ap) { list_for_each_entry_rcu(list_p, &ap->list, list) |
1f0ab4097
|
1461 1462 1463 1464 1465 1466 |
if (list_p == p) /* kprobe p is a valid probe */ goto valid; return NULL; } valid: |
6d8e40a85
|
1467 |
return ap; |
1f0ab4097
|
1468 1469 1470 1471 1472 1473 |
} /* Return error if the kprobe is being re-registered */ static inline int check_kprobe_rereg(struct kprobe *p) { int ret = 0; |
1f0ab4097
|
1474 1475 |
mutex_lock(&kprobe_mutex); |
6d8e40a85
|
1476 |
if (__get_valid_kprobe(p)) |
1f0ab4097
|
1477 1478 |
ret = -EINVAL; mutex_unlock(&kprobe_mutex); |
6d8e40a85
|
1479 |
|
1f0ab4097
|
1480 1481 |
return ret; } |
f7f242ff0
|
1482 |
int __weak arch_check_ftrace_location(struct kprobe *p) |
1da177e4c
|
1483 |
{ |
ae6aa16fd
|
1484 |
unsigned long ftrace_addr; |
ae6aa16fd
|
1485 1486 |
ftrace_addr = ftrace_location((unsigned long)p->addr); if (ftrace_addr) { |
e7dbfe349
|
1487 |
#ifdef CONFIG_KPROBES_ON_FTRACE |
ae6aa16fd
|
1488 1489 1490 |
/* Given address is not on the instruction boundary */ if ((unsigned long)p->addr != ftrace_addr) return -EILSEQ; |
ae6aa16fd
|
1491 |
p->flags |= KPROBE_FLAG_FTRACE; |
e7dbfe349
|
1492 |
#else /* !CONFIG_KPROBES_ON_FTRACE */ |
ae6aa16fd
|
1493 1494 1495 |
return -EINVAL; #endif } |
f7f242ff0
|
1496 1497 1498 1499 1500 1501 1502 |
return 0; } static int check_kprobe_address_safe(struct kprobe *p, struct module **probed_mod) { int ret; |
1f0ab4097
|
1503 |
|
f7f242ff0
|
1504 1505 1506 |
ret = arch_check_ftrace_location(p); if (ret) return ret; |
91bad2f8d
|
1507 |
jump_label_lock(); |
de31c3ca8
|
1508 |
preempt_disable(); |
f7fa6ef0d
|
1509 1510 |
/* Ensure it is not in reserved area nor out of text */ |
ec30c5f3a
|
1511 |
if (!kernel_text_address((unsigned long) p->addr) || |
376e24242
|
1512 |
within_kprobe_blacklist((unsigned long) p->addr) || |
e336b4027
|
1513 1514 |
jump_label_text_reserved(p->addr, p->addr) || find_bug((unsigned long)p->addr)) { |
f986a499e
|
1515 |
ret = -EINVAL; |
f7fa6ef0d
|
1516 |
goto out; |
f986a499e
|
1517 |
} |
b3e55c727
|
1518 |
|
f7fa6ef0d
|
1519 1520 1521 |
/* Check if are we probing a module */ *probed_mod = __module_text_address((unsigned long) p->addr); if (*probed_mod) { |
6f716acd5
|
1522 |
/* |
e8386a0cb
|
1523 1524 |
* We must hold a refcount of the probed module while updating * its code to prohibit unexpected unloading. |
df019b1d8
|
1525 |
*/ |
f7fa6ef0d
|
1526 1527 1528 1529 |
if (unlikely(!try_module_get(*probed_mod))) { ret = -ENOENT; goto out; } |
de31c3ca8
|
1530 |
|
f24659d96
|
1531 1532 1533 1534 |
/* * If the module freed .init.text, we couldn't insert * kprobes in there. */ |
f7fa6ef0d
|
1535 1536 1537 1538 1539 |
if (within_module_init((unsigned long)p->addr, *probed_mod) && (*probed_mod)->state != MODULE_STATE_COMING) { module_put(*probed_mod); *probed_mod = NULL; ret = -ENOENT; |
f24659d96
|
1540 |
} |
df019b1d8
|
1541 |
} |
f7fa6ef0d
|
1542 |
out: |
a189d0350
|
1543 |
preempt_enable(); |
de31c3ca8
|
1544 |
jump_label_unlock(); |
1da177e4c
|
1545 |
|
f7fa6ef0d
|
1546 1547 |
return ret; } |
55479f647
|
1548 |
int register_kprobe(struct kprobe *p) |
f7fa6ef0d
|
1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 |
{ int ret; struct kprobe *old_p; struct module *probed_mod; kprobe_opcode_t *addr; /* Adjust probe address from symbol */ addr = kprobe_addr(p); if (IS_ERR(addr)) return PTR_ERR(addr); p->addr = addr; ret = check_kprobe_rereg(p); if (ret) return ret; /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ p->flags &= KPROBE_FLAG_DISABLED; |
3516a4604
|
1567 |
p->nmissed = 0; |
9861668f7
|
1568 |
INIT_LIST_HEAD(&p->list); |
afd66255b
|
1569 |
|
f7fa6ef0d
|
1570 1571 1572 1573 1574 |
ret = check_kprobe_address_safe(p, &probed_mod); if (ret) return ret; mutex_lock(&kprobe_mutex); |
afd66255b
|
1575 |
|
64f562c6d
|
1576 1577 |
old_p = get_kprobe(p->addr); if (old_p) { |
afd66255b
|
1578 |
/* Since this may unoptimize old_p, locking text_mutex. */ |
64f562c6d
|
1579 |
ret = register_aggr_kprobe(old_p, p); |
1da177e4c
|
1580 1581 |
goto out; } |
1da177e4c
|
1582 |
|
2d1e38f56
|
1583 1584 1585 |
cpus_read_lock(); /* Prevent text modification */ mutex_lock(&text_mutex); |
ae6aa16fd
|
1586 |
ret = prepare_kprobe(p); |
25764288d
|
1587 |
mutex_unlock(&text_mutex); |
2d1e38f56
|
1588 |
cpus_read_unlock(); |
6f716acd5
|
1589 |
if (ret) |
afd66255b
|
1590 |
goto out; |
49a2a1b83
|
1591 |
|
64f562c6d
|
1592 |
INIT_HLIST_NODE(&p->hlist); |
3516a4604
|
1593 |
hlist_add_head_rcu(&p->hlist, |
1da177e4c
|
1594 |
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); |
12310e343
|
1595 1596 1597 1598 |
if (!kprobes_all_disarmed && !kprobe_disabled(p)) { ret = arm_kprobe(p); if (ret) { hlist_del_rcu(&p->hlist); |
ae8b7ce76
|
1599 |
synchronize_rcu(); |
12310e343
|
1600 1601 1602 |
goto out; } } |
afd66255b
|
1603 1604 1605 |
/* Try to optimize kprobe */ try_to_optimize_kprobe(p); |
1da177e4c
|
1606 |
out: |
7a7d1cf95
|
1607 |
mutex_unlock(&kprobe_mutex); |
49a2a1b83
|
1608 |
|
e8386a0cb
|
1609 |
if (probed_mod) |
df019b1d8
|
1610 |
module_put(probed_mod); |
e8386a0cb
|
1611 |
|
1da177e4c
|
1612 1613 |
return ret; } |
99081ab55
|
1614 |
EXPORT_SYMBOL_GPL(register_kprobe); |
1da177e4c
|
1615 |
|
6f0f1dd71
|
1616 |
/* Check if all probes on the aggrprobe are disabled */ |
55479f647
|
1617 |
static int aggr_kprobe_disabled(struct kprobe *ap) |
6f0f1dd71
|
1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 |
{ struct kprobe *kp; list_for_each_entry_rcu(kp, &ap->list, list) if (!kprobe_disabled(kp)) /* * There is an active probe on the list. * We can't disable this ap. */ return 0; return 1; } /* Disable one kprobe: Make sure called under kprobe_mutex is locked */ |
55479f647
|
1633 |
static struct kprobe *__disable_kprobe(struct kprobe *p) |
6f0f1dd71
|
1634 1635 |
{ struct kprobe *orig_p; |
297f9233b
|
1636 |
int ret; |
6f0f1dd71
|
1637 1638 1639 1640 |
/* Get an original kprobe for return */ orig_p = __get_valid_kprobe(p); if (unlikely(orig_p == NULL)) |
297f9233b
|
1641 |
return ERR_PTR(-EINVAL); |
6f0f1dd71
|
1642 1643 1644 1645 1646 1647 1648 1649 |
if (!kprobe_disabled(p)) { /* Disable probe if it is a child probe */ if (p != orig_p) p->flags |= KPROBE_FLAG_DISABLED; /* Try to disarm and disable this/parent probe */ if (p == orig_p || aggr_kprobe_disabled(orig_p)) { |
69d54b916
|
1650 1651 1652 1653 1654 |
/* * If kprobes_all_disarmed is set, orig_p * should have already been disarmed, so * skip unneed disarming process. */ |
297f9233b
|
1655 1656 1657 1658 1659 1660 1661 |
if (!kprobes_all_disarmed) { ret = disarm_kprobe(orig_p, true); if (ret) { p->flags &= ~KPROBE_FLAG_DISABLED; return ERR_PTR(ret); } } |
6f0f1dd71
|
1662 1663 1664 1665 1666 1667 |
orig_p->flags |= KPROBE_FLAG_DISABLED; } } return orig_p; } |
de5bd88d5
|
1668 1669 1670 |
/* * Unregister a kprobe without a scheduler synchronization. */ |
55479f647
|
1671 |
static int __unregister_kprobe_top(struct kprobe *p) |
de5bd88d5
|
1672 |
{ |
6d8e40a85
|
1673 |
struct kprobe *ap, *list_p; |
de5bd88d5
|
1674 |
|
6f0f1dd71
|
1675 1676 |
/* Disable kprobe. This will disarm it if needed. */ ap = __disable_kprobe(p); |
297f9233b
|
1677 1678 |
if (IS_ERR(ap)) return PTR_ERR(ap); |
de5bd88d5
|
1679 |
|
6f0f1dd71
|
1680 |
if (ap == p) |
bf8f6e5b3
|
1681 |
/* |
6f0f1dd71
|
1682 1683 |
* This probe is an independent(and non-optimized) kprobe * (not an aggrprobe). Remove from the hash list. |
bf8f6e5b3
|
1684 |
*/ |
6f0f1dd71
|
1685 1686 1687 1688 |
goto disarmed; /* Following process expects this probe is an aggrprobe */ WARN_ON(!kprobe_aggrprobe(ap)); |
6274de498
|
1689 1690 1691 1692 1693 |
if (list_is_singular(&ap->list) && kprobe_disarmed(ap)) /* * !disarmed could be happen if the probe is under delayed * unoptimizing. */ |
6f0f1dd71
|
1694 1695 1696 |
goto disarmed; else { /* If disabling probe has special handlers, update aggrprobe */ |
e8386a0cb
|
1697 |
if (p->post_handler && !kprobe_gone(p)) { |
6d8e40a85
|
1698 |
list_for_each_entry_rcu(list_p, &ap->list, list) { |
9861668f7
|
1699 1700 1701 |
if ((list_p != p) && (list_p->post_handler)) goto noclean; } |
6d8e40a85
|
1702 |
ap->post_handler = NULL; |
9861668f7
|
1703 1704 |
} noclean: |
6f0f1dd71
|
1705 1706 1707 1708 |
/* * Remove from the aggrprobe: this path will do nothing in * __unregister_kprobe_bottom(). */ |
49a2a1b83
|
1709 |
list_del_rcu(&p->list); |
6f0f1dd71
|
1710 1711 1712 1713 1714 1715 |
if (!kprobe_disabled(ap) && !kprobes_all_disarmed) /* * Try to optimize this probe again, because post * handler may have been changed. */ optimize_kprobe(ap); |
49a2a1b83
|
1716 |
} |
9861668f7
|
1717 |
return 0; |
6f0f1dd71
|
1718 1719 1720 1721 |
disarmed: hlist_del_rcu(&ap->hlist); return 0; |
9861668f7
|
1722 |
} |
3516a4604
|
1723 |
|
55479f647
|
1724 |
static void __unregister_kprobe_bottom(struct kprobe *p) |
9861668f7
|
1725 |
{ |
6d8e40a85
|
1726 |
struct kprobe *ap; |
b3e55c727
|
1727 |
|
e8386a0cb
|
1728 |
if (list_empty(&p->list)) |
6274de498
|
1729 |
/* This is an independent kprobe */ |
0498b6350
|
1730 |
arch_remove_kprobe(p); |
e8386a0cb
|
1731 |
else if (list_is_singular(&p->list)) { |
6274de498
|
1732 |
/* This is the last child of an aggrprobe */ |
6d8e40a85
|
1733 |
ap = list_entry(p->list.next, struct kprobe, list); |
e8386a0cb
|
1734 |
list_del(&p->list); |
6d8e40a85
|
1735 |
free_aggr_kprobe(ap); |
9861668f7
|
1736 |
} |
6274de498
|
1737 |
/* Otherwise, do nothing. */ |
9861668f7
|
1738 |
} |
55479f647
|
1739 |
int register_kprobes(struct kprobe **kps, int num) |
9861668f7
|
1740 1741 1742 1743 1744 1745 |
{ int i, ret = 0; if (num <= 0) return -EINVAL; for (i = 0; i < num; i++) { |
49ad2fd76
|
1746 |
ret = register_kprobe(kps[i]); |
67dddaad5
|
1747 1748 1749 |
if (ret < 0) { if (i > 0) unregister_kprobes(kps, i); |
9861668f7
|
1750 |
break; |
367216567
|
1751 |
} |
49a2a1b83
|
1752 |
} |
9861668f7
|
1753 1754 |
return ret; } |
99081ab55
|
1755 |
EXPORT_SYMBOL_GPL(register_kprobes); |
9861668f7
|
1756 |
|
55479f647
|
1757 |
void unregister_kprobe(struct kprobe *p) |
9861668f7
|
1758 1759 1760 |
{ unregister_kprobes(&p, 1); } |
99081ab55
|
1761 |
EXPORT_SYMBOL_GPL(unregister_kprobe); |
9861668f7
|
1762 |
|
55479f647
|
1763 |
void unregister_kprobes(struct kprobe **kps, int num) |
9861668f7
|
1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 |
{ int i; if (num <= 0) return; mutex_lock(&kprobe_mutex); for (i = 0; i < num; i++) if (__unregister_kprobe_top(kps[i]) < 0) kps[i]->addr = NULL; mutex_unlock(&kprobe_mutex); |
ae8b7ce76
|
1774 |
synchronize_rcu(); |
9861668f7
|
1775 1776 1777 |
for (i = 0; i < num; i++) if (kps[i]->addr) __unregister_kprobe_bottom(kps[i]); |
1da177e4c
|
1778 |
} |
99081ab55
|
1779 |
EXPORT_SYMBOL_GPL(unregister_kprobes); |
1da177e4c
|
1780 |
|
5f6bee347
|
1781 1782 |
int __weak kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data) |
fc62d0207
|
1783 1784 1785 |
{ return NOTIFY_DONE; } |
5f6bee347
|
1786 |
NOKPROBE_SYMBOL(kprobe_exceptions_notify); |
fc62d0207
|
1787 |
|
1da177e4c
|
1788 1789 |
static struct notifier_block kprobe_exceptions_nb = { .notifier_call = kprobe_exceptions_notify, |
3d5631e06
|
1790 1791 |
.priority = 0x7fffffff /* we need to be notified first */ }; |
3d7e33825
|
1792 1793 1794 1795 |
unsigned long __weak arch_deref_entry_point(void *entry) { return (unsigned long)entry; } |
1da177e4c
|
1796 |
|
9edddaa20
|
1797 |
#ifdef CONFIG_KRETPROBES |
e65cefe87
|
1798 1799 1800 1801 |
/* * This kprobe pre_handler is registered with every kretprobe. When probe * hits it will set up the return probe. */ |
820aede02
|
1802 |
static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
e65cefe87
|
1803 1804 |
{ struct kretprobe *rp = container_of(p, struct kretprobe, kp); |
ef53d9c5e
|
1805 1806 |
unsigned long hash, flags = 0; struct kretprobe_instance *ri; |
e65cefe87
|
1807 |
|
f96f56780
|
1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 |
/* * To avoid deadlocks, prohibit return probing in NMI contexts, * just skip the probe and increase the (inexact) 'nmissed' * statistical counter, so that the user is informed that * something happened: */ if (unlikely(in_nmi())) { rp->nmissed++; return 0; } /* TODO: consider to only swap the RA after the last pre_handler fired */ |
ef53d9c5e
|
1820 |
hash = hash_ptr(current, KPROBE_HASH_BITS); |
ec484608c
|
1821 |
raw_spin_lock_irqsave(&rp->lock, flags); |
4c4308cb9
|
1822 |
if (!hlist_empty(&rp->free_instances)) { |
4c4308cb9
|
1823 |
ri = hlist_entry(rp->free_instances.first, |
ef53d9c5e
|
1824 1825 |
struct kretprobe_instance, hlist); hlist_del(&ri->hlist); |
ec484608c
|
1826 |
raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5e
|
1827 |
|
4c4308cb9
|
1828 1829 |
ri->rp = rp; ri->task = current; |
f47cd9b55
|
1830 |
|
55ca6140e
|
1831 1832 1833 1834 |
if (rp->entry_handler && rp->entry_handler(ri, regs)) { raw_spin_lock_irqsave(&rp->lock, flags); hlist_add_head(&ri->hlist, &rp->free_instances); raw_spin_unlock_irqrestore(&rp->lock, flags); |
f47cd9b55
|
1835 |
return 0; |
55ca6140e
|
1836 |
} |
f47cd9b55
|
1837 |
|
4c4308cb9
|
1838 1839 1840 |
arch_prepare_kretprobe(ri, regs); /* XXX(hch): why is there no hlist_move_head? */ |
ef53d9c5e
|
1841 1842 1843 1844 1845 |
INIT_HLIST_NODE(&ri->hlist); kretprobe_table_lock(hash, &flags); hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]); kretprobe_table_unlock(hash, &flags); } else { |
4c4308cb9
|
1846 |
rp->nmissed++; |
ec484608c
|
1847 |
raw_spin_unlock_irqrestore(&rp->lock, flags); |
ef53d9c5e
|
1848 |
} |
e65cefe87
|
1849 1850 |
return 0; } |
820aede02
|
1851 |
NOKPROBE_SYMBOL(pre_handler_kretprobe); |
e65cefe87
|
1852 |
|
659b957f2
|
1853 |
bool __weak arch_kprobe_on_func_entry(unsigned long offset) |
90ec5e89e
|
1854 1855 1856 |
{ return !offset; } |
659b957f2
|
1857 |
bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset) |
1d585e709
|
1858 1859 1860 1861 1862 1863 1864 |
{ kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset); if (IS_ERR(kp_addr)) return false; if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset) || |
659b957f2
|
1865 |
!arch_kprobe_on_func_entry(offset)) |
1d585e709
|
1866 1867 1868 1869 |
return false; return true; } |
55479f647
|
1870 |
int register_kretprobe(struct kretprobe *rp) |
b94cce926
|
1871 1872 1873 1874 |
{ int ret = 0; struct kretprobe_instance *inst; int i; |
b2a5cd693
|
1875 |
void *addr; |
90ec5e89e
|
1876 |
|
659b957f2
|
1877 |
if (!kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset)) |
90ec5e89e
|
1878 |
return -EINVAL; |
f438d914b
|
1879 1880 |
if (kretprobe_blacklist_size) { |
b2a5cd693
|
1881 |
addr = kprobe_addr(&rp->kp); |
bc81d48d1
|
1882 1883 |
if (IS_ERR(addr)) return PTR_ERR(addr); |
f438d914b
|
1884 1885 1886 1887 1888 1889 |
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { if (kretprobe_blacklist[i].addr == addr) return -EINVAL; } } |
b94cce926
|
1890 1891 |
rp->kp.pre_handler = pre_handler_kretprobe; |
7522a8423
|
1892 1893 |
rp->kp.post_handler = NULL; rp->kp.fault_handler = NULL; |
b94cce926
|
1894 1895 1896 |
/* Pre-allocate memory for max kretprobe instances */ if (rp->maxactive <= 0) { |
926166063
|
1897 |
#ifdef CONFIG_PREEMPTION |
c2ef6661c
|
1898 |
rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); |
b94cce926
|
1899 |
#else |
4dae560f9
|
1900 |
rp->maxactive = num_possible_cpus(); |
b94cce926
|
1901 1902 |
#endif } |
ec484608c
|
1903 |
raw_spin_lock_init(&rp->lock); |
b94cce926
|
1904 1905 |
INIT_HLIST_HEAD(&rp->free_instances); for (i = 0; i < rp->maxactive; i++) { |
f47cd9b55
|
1906 1907 |
inst = kmalloc(sizeof(struct kretprobe_instance) + rp->data_size, GFP_KERNEL); |
b94cce926
|
1908 1909 1910 1911 |
if (inst == NULL) { free_rp_inst(rp); return -ENOMEM; } |
ef53d9c5e
|
1912 1913 |
INIT_HLIST_NODE(&inst->hlist); hlist_add_head(&inst->hlist, &rp->free_instances); |
b94cce926
|
1914 1915 1916 1917 |
} rp->nmissed = 0; /* Establish function entry probe point */ |
49ad2fd76
|
1918 |
ret = register_kprobe(&rp->kp); |
4a296e07c
|
1919 |
if (ret != 0) |
b94cce926
|
1920 1921 1922 |
free_rp_inst(rp); return ret; } |
99081ab55
|
1923 |
EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce926
|
1924 |
|
55479f647
|
1925 |
int register_kretprobes(struct kretprobe **rps, int num) |
4a296e07c
|
1926 1927 1928 1929 1930 1931 |
{ int ret = 0, i; if (num <= 0) return -EINVAL; for (i = 0; i < num; i++) { |
49ad2fd76
|
1932 |
ret = register_kretprobe(rps[i]); |
67dddaad5
|
1933 1934 1935 |
if (ret < 0) { if (i > 0) unregister_kretprobes(rps, i); |
4a296e07c
|
1936 1937 1938 1939 1940 |
break; } } return ret; } |
99081ab55
|
1941 |
EXPORT_SYMBOL_GPL(register_kretprobes); |
4a296e07c
|
1942 |
|
55479f647
|
1943 |
void unregister_kretprobe(struct kretprobe *rp) |
4a296e07c
|
1944 1945 1946 |
{ unregister_kretprobes(&rp, 1); } |
99081ab55
|
1947 |
EXPORT_SYMBOL_GPL(unregister_kretprobe); |
4a296e07c
|
1948 |
|
55479f647
|
1949 |
void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07c
|
1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 |
{ int i; if (num <= 0) return; mutex_lock(&kprobe_mutex); for (i = 0; i < num; i++) if (__unregister_kprobe_top(&rps[i]->kp) < 0) rps[i]->kp.addr = NULL; mutex_unlock(&kprobe_mutex); |
ae8b7ce76
|
1960 |
synchronize_rcu(); |
4a296e07c
|
1961 1962 1963 1964 1965 1966 1967 |
for (i = 0; i < num; i++) { if (rps[i]->kp.addr) { __unregister_kprobe_bottom(&rps[i]->kp); cleanup_rp_inst(rps[i]); } } } |
99081ab55
|
1968 |
EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4a296e07c
|
1969 |
|
9edddaa20
|
1970 |
#else /* CONFIG_KRETPROBES */ |
55479f647
|
1971 |
int register_kretprobe(struct kretprobe *rp) |
b94cce926
|
1972 1973 1974 |
{ return -ENOSYS; } |
99081ab55
|
1975 |
EXPORT_SYMBOL_GPL(register_kretprobe); |
b94cce926
|
1976 |
|
55479f647
|
1977 |
int register_kretprobes(struct kretprobe **rps, int num) |
346fd59ba
|
1978 |
{ |
4a296e07c
|
1979 |
return -ENOSYS; |
346fd59ba
|
1980 |
} |
99081ab55
|
1981 |
EXPORT_SYMBOL_GPL(register_kretprobes); |
55479f647
|
1982 |
void unregister_kretprobe(struct kretprobe *rp) |
b94cce926
|
1983 |
{ |
4a296e07c
|
1984 |
} |
99081ab55
|
1985 |
EXPORT_SYMBOL_GPL(unregister_kretprobe); |
b94cce926
|
1986 |
|
55479f647
|
1987 |
void unregister_kretprobes(struct kretprobe **rps, int num) |
4a296e07c
|
1988 1989 |
{ } |
99081ab55
|
1990 |
EXPORT_SYMBOL_GPL(unregister_kretprobes); |
4c4308cb9
|
1991 |
|
820aede02
|
1992 |
static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs) |
4a296e07c
|
1993 1994 |
{ return 0; |
b94cce926
|
1995 |
} |
820aede02
|
1996 |
NOKPROBE_SYMBOL(pre_handler_kretprobe); |
b94cce926
|
1997 |
|
4a296e07c
|
1998 |
#endif /* CONFIG_KRETPROBES */ |
e8386a0cb
|
1999 |
/* Set the kprobe gone and remove its instruction buffer. */ |
55479f647
|
2000 |
static void kill_kprobe(struct kprobe *p) |
e8386a0cb
|
2001 2002 |
{ struct kprobe *kp; |
de5bd88d5
|
2003 |
|
e8386a0cb
|
2004 |
p->flags |= KPROBE_FLAG_GONE; |
afd66255b
|
2005 |
if (kprobe_aggrprobe(p)) { |
e8386a0cb
|
2006 2007 2008 2009 2010 2011 2012 |
/* * If this is an aggr_kprobe, we have to list all the * chained probes and mark them GONE. */ list_for_each_entry_rcu(kp, &p->list, list) kp->flags |= KPROBE_FLAG_GONE; p->post_handler = NULL; |
afd66255b
|
2013 |
kill_optimized_kprobe(p); |
e8386a0cb
|
2014 2015 2016 2017 2018 2019 2020 |
} /* * Here, we can remove insn_slot safely, because no thread calls * the original probed function (which will be freed soon) any more. */ arch_remove_kprobe(p); } |
c0614829c
|
2021 |
/* Disable one kprobe */ |
55479f647
|
2022 |
int disable_kprobe(struct kprobe *kp) |
c0614829c
|
2023 2024 |
{ int ret = 0; |
297f9233b
|
2025 |
struct kprobe *p; |
c0614829c
|
2026 2027 |
mutex_lock(&kprobe_mutex); |
6f0f1dd71
|
2028 |
/* Disable this kprobe */ |
297f9233b
|
2029 2030 2031 |
p = __disable_kprobe(kp); if (IS_ERR(p)) ret = PTR_ERR(p); |
c0614829c
|
2032 |
|
c0614829c
|
2033 2034 2035 2036 2037 2038 |
mutex_unlock(&kprobe_mutex); return ret; } EXPORT_SYMBOL_GPL(disable_kprobe); /* Enable one kprobe */ |
55479f647
|
2039 |
int enable_kprobe(struct kprobe *kp) |
c0614829c
|
2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 |
{ int ret = 0; struct kprobe *p; mutex_lock(&kprobe_mutex); /* Check whether specified probe is valid. */ p = __get_valid_kprobe(kp); if (unlikely(p == NULL)) { ret = -EINVAL; goto out; } if (kprobe_gone(kp)) { /* This kprobe has gone, we couldn't enable it. */ ret = -EINVAL; goto out; } if (p != kp) kp->flags &= ~KPROBE_FLAG_DISABLED; if (!kprobes_all_disarmed && kprobe_disabled(p)) { p->flags &= ~KPROBE_FLAG_DISABLED; |
12310e343
|
2064 2065 2066 |
ret = arm_kprobe(p); if (ret) p->flags |= KPROBE_FLAG_DISABLED; |
c0614829c
|
2067 2068 2069 2070 2071 2072 |
} out: mutex_unlock(&kprobe_mutex); return ret; } EXPORT_SYMBOL_GPL(enable_kprobe); |
4458515b2
|
2073 |
/* Caller must NOT call this in usual path. This is only for critical case */ |
820aede02
|
2074 |
void dump_kprobe(struct kprobe *kp) |
24851d244
|
2075 |
{ |
4458515b2
|
2076 2077 2078 2079 2080 2081 2082 |
pr_err("Dumping kprobe: "); pr_err("Name: %s Offset: %x Address: %pS ", kp->symbol_name, kp->offset, kp->addr); |
24851d244
|
2083 |
} |
820aede02
|
2084 |
NOKPROBE_SYMBOL(dump_kprobe); |
24851d244
|
2085 |
|
fb1a59fae
|
2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 |
int kprobe_add_ksym_blacklist(unsigned long entry) { struct kprobe_blacklist_entry *ent; unsigned long offset = 0, size = 0; if (!kernel_text_address(entry) || !kallsyms_lookup_size_offset(entry, &size, &offset)) return -EINVAL; ent = kmalloc(sizeof(*ent), GFP_KERNEL); if (!ent) return -ENOMEM; ent->start_addr = entry; ent->end_addr = entry + size; INIT_LIST_HEAD(&ent->list); list_add_tail(&ent->list, &kprobe_blacklist); return (int)size; } /* Add all symbols in given area into kprobe blacklist */ int kprobe_add_area_blacklist(unsigned long start, unsigned long end) { unsigned long entry; int ret = 0; for (entry = start; entry < end; entry += ret) { ret = kprobe_add_ksym_blacklist(entry); if (ret < 0) return ret; if (ret == 0) /* In case of alias symbol */ ret = 1; } return 0; } int __init __weak arch_populate_kprobe_blacklist(void) { return 0; } |
376e24242
|
2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 |
/* * Lookup and populate the kprobe_blacklist. * * Unlike the kretprobe blacklist, we'll need to determine * the range of addresses that belong to the said functions, * since a kprobe need not necessarily be at the beginning * of a function. */ static int __init populate_kprobe_blacklist(unsigned long *start, unsigned long *end) { |
fb1a59fae
|
2137 |
unsigned long entry; |
376e24242
|
2138 |
unsigned long *iter; |
fb1a59fae
|
2139 |
int ret; |
376e24242
|
2140 2141 |
for (iter = start; iter < end; iter++) { |
d81b4253b
|
2142 |
entry = arch_deref_entry_point((void *)*iter); |
fb1a59fae
|
2143 2144 |
ret = kprobe_add_ksym_blacklist(entry); if (ret == -EINVAL) |
376e24242
|
2145 |
continue; |
fb1a59fae
|
2146 2147 |
if (ret < 0) return ret; |
376e24242
|
2148 |
} |
fb1a59fae
|
2149 2150 2151 2152 2153 2154 |
/* Symbols in __kprobes_text are blacklisted */ ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start, (unsigned long)__kprobes_text_end); return ret ? : arch_populate_kprobe_blacklist(); |
376e24242
|
2155 |
} |
e8386a0cb
|
2156 |
/* Module notifier call back, checking kprobes on the module */ |
55479f647
|
2157 2158 |
static int kprobes_module_callback(struct notifier_block *nb, unsigned long val, void *data) |
e8386a0cb
|
2159 2160 2161 |
{ struct module *mod = data; struct hlist_head *head; |
e8386a0cb
|
2162 2163 |
struct kprobe *p; unsigned int i; |
f24659d96
|
2164 |
int checkcore = (val == MODULE_STATE_GOING); |
e8386a0cb
|
2165 |
|
f24659d96
|
2166 |
if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) |
e8386a0cb
|
2167 2168 2169 |
return NOTIFY_DONE; /* |
f24659d96
|
2170 2171 2172 2173 |
* When MODULE_STATE_GOING was notified, both of module .text and * .init.text sections would be freed. When MODULE_STATE_LIVE was * notified, only .init.text section would be freed. We need to * disable kprobes which have been inserted in the sections. |
e8386a0cb
|
2174 2175 2176 2177 |
*/ mutex_lock(&kprobe_mutex); for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; |
b67bfe0d4
|
2178 |
hlist_for_each_entry_rcu(p, head, hlist) |
f24659d96
|
2179 2180 2181 |
if (within_module_init((unsigned long)p->addr, mod) || (checkcore && within_module_core((unsigned long)p->addr, mod))) { |
e8386a0cb
|
2182 2183 2184 2185 |
/* * The vaddr this probe is installed will soon * be vfreed buy not synced to disk. Hence, * disarming the breakpoint isn't needed. |
545a02819
|
2186 2187 2188 2189 2190 2191 |
* * Note, this will also move any optimized probes * that are pending to be removed from their * corresponding lists to the freeing_list and * will not be touched by the delayed * kprobe_optimizer work handler. |
e8386a0cb
|
2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 |
*/ kill_kprobe(p); } } mutex_unlock(&kprobe_mutex); return NOTIFY_DONE; } static struct notifier_block kprobe_module_nb = { .notifier_call = kprobes_module_callback, .priority = 0 }; |
376e24242
|
2204 2205 2206 |
/* Markers of _kprobe_blacklist section */ extern unsigned long __start_kprobe_blacklist[]; extern unsigned long __stop_kprobe_blacklist[]; |
1da177e4c
|
2207 2208 2209 2210 2211 2212 |
static int __init init_kprobes(void) { int i, err = 0; /* FIXME allocate the probe table, currently defined statically */ /* initialize all list heads */ |
b94cce926
|
2213 |
for (i = 0; i < KPROBE_TABLE_SIZE; i++) { |
1da177e4c
|
2214 |
INIT_HLIST_HEAD(&kprobe_table[i]); |
b94cce926
|
2215 |
INIT_HLIST_HEAD(&kretprobe_inst_table[i]); |
ec484608c
|
2216 |
raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); |
b94cce926
|
2217 |
} |
1da177e4c
|
2218 |
|
376e24242
|
2219 2220 2221 2222 2223 2224 2225 |
err = populate_kprobe_blacklist(__start_kprobe_blacklist, __stop_kprobe_blacklist); if (err) { pr_err("kprobes: failed to populate blacklist: %d ", err); pr_err("Please take care of using kprobes. "); |
3d8d996e0
|
2226 |
} |
f438d914b
|
2227 2228 2229 |
if (kretprobe_blacklist_size) { /* lookup the function address from its name */ for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |
49e0b4658
|
2230 |
kretprobe_blacklist[i].addr = |
290e30707
|
2231 |
kprobe_lookup_name(kretprobe_blacklist[i].name, 0); |
f438d914b
|
2232 2233 2234 2235 2236 2237 |
if (!kretprobe_blacklist[i].addr) printk("kretprobe: lookup failed: %s ", kretprobe_blacklist[i].name); } } |
b2be84df9
|
2238 2239 |
#if defined(CONFIG_OPTPROBES) #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) |
afd66255b
|
2240 2241 2242 |
/* Init kprobe_optinsn_slots */ kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; #endif |
b2be84df9
|
2243 2244 2245 |
/* By default, kprobes can be optimized */ kprobes_allow_optimization = true; #endif |
afd66255b
|
2246 |
|
e579abeb5
|
2247 2248 |
/* By default, kprobes are armed */ kprobes_all_disarmed = false; |
bf8f6e5b3
|
2249 |
|
6772926be
|
2250 |
err = arch_init_kprobes(); |
802eae7c8
|
2251 2252 |
if (!err) err = register_die_notifier(&kprobe_exceptions_nb); |
e8386a0cb
|
2253 2254 |
if (!err) err = register_module_notifier(&kprobe_module_nb); |
ef53d9c5e
|
2255 |
kprobes_initialized = (err == 0); |
802eae7c8
|
2256 |
|
8c1c93564
|
2257 2258 |
if (!err) init_test_probes(); |
1da177e4c
|
2259 2260 |
return err; } |
65fc965c7
|
2261 |
subsys_initcall(init_kprobes); |
1da177e4c
|
2262 |
|
346fd59ba
|
2263 |
#ifdef CONFIG_DEBUG_FS |
55479f647
|
2264 |
static void report_probe(struct seq_file *pi, struct kprobe *p, |
afd66255b
|
2265 |
const char *sym, int offset, char *modname, struct kprobe *pp) |
346fd59ba
|
2266 2267 |
{ char *kprobe_type; |
81365a947
|
2268 |
void *addr = p->addr; |
346fd59ba
|
2269 2270 2271 |
if (p->pre_handler == pre_handler_kretprobe) kprobe_type = "r"; |
346fd59ba
|
2272 2273 |
else kprobe_type = "k"; |
afd66255b
|
2274 |
|
e5541c634
|
2275 |
if (!kallsyms_show_value(pi->file->f_cred)) |
81365a947
|
2276 |
addr = NULL; |
346fd59ba
|
2277 |
if (sym) |
81365a947
|
2278 2279 |
seq_printf(pi, "%px %s %s+0x%x %s ", addr, kprobe_type, sym, offset, |
afd66255b
|
2280 |
(modname ? modname : " ")); |
81365a947
|
2281 2282 2283 |
else /* try to use %pS */ seq_printf(pi, "%px %s %pS ", addr, kprobe_type, p->addr); |
afd66255b
|
2284 2285 2286 |
if (!pp) pp = p; |
ae6aa16fd
|
2287 2288 |
seq_printf(pi, "%s%s%s%s ", |
afd66255b
|
2289 2290 |
(kprobe_gone(p) ? "[GONE]" : ""), ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""), |
ae6aa16fd
|
2291 2292 |
(kprobe_optimized(pp) ? "[OPTIMIZED]" : ""), (kprobe_ftrace(pp) ? "[FTRACE]" : "")); |
346fd59ba
|
2293 |
} |
55479f647
|
2294 |
static void *kprobe_seq_start(struct seq_file *f, loff_t *pos) |
346fd59ba
|
2295 2296 2297 |
{ return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL; } |
55479f647
|
2298 |
static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos) |
346fd59ba
|
2299 2300 2301 2302 2303 2304 |
{ (*pos)++; if (*pos >= KPROBE_TABLE_SIZE) return NULL; return pos; } |
55479f647
|
2305 |
static void kprobe_seq_stop(struct seq_file *f, void *v) |
346fd59ba
|
2306 2307 2308 |
{ /* Nothing to do */ } |
55479f647
|
2309 |
static int show_kprobe_addr(struct seq_file *pi, void *v) |
346fd59ba
|
2310 2311 |
{ struct hlist_head *head; |
346fd59ba
|
2312 2313 2314 |
struct kprobe *p, *kp; const char *sym = NULL; unsigned int i = *(loff_t *) v; |
ffb451227
|
2315 |
unsigned long offset = 0; |
ab7678656
|
2316 |
char *modname, namebuf[KSYM_NAME_LEN]; |
346fd59ba
|
2317 2318 2319 |
head = &kprobe_table[i]; preempt_disable(); |
b67bfe0d4
|
2320 |
hlist_for_each_entry_rcu(p, head, hlist) { |
ffb451227
|
2321 |
sym = kallsyms_lookup((unsigned long)p->addr, NULL, |
346fd59ba
|
2322 |
&offset, &modname, namebuf); |
afd66255b
|
2323 |
if (kprobe_aggrprobe(p)) { |
346fd59ba
|
2324 |
list_for_each_entry_rcu(kp, &p->list, list) |
afd66255b
|
2325 |
report_probe(pi, kp, sym, offset, modname, p); |
346fd59ba
|
2326 |
} else |
afd66255b
|
2327 |
report_probe(pi, p, sym, offset, modname, NULL); |
346fd59ba
|
2328 2329 2330 2331 |
} preempt_enable(); return 0; } |
88e9d34c7
|
2332 |
static const struct seq_operations kprobes_seq_ops = { |
346fd59ba
|
2333 2334 2335 2336 2337 |
.start = kprobe_seq_start, .next = kprobe_seq_next, .stop = kprobe_seq_stop, .show = show_kprobe_addr }; |
55479f647
|
2338 |
static int kprobes_open(struct inode *inode, struct file *filp) |
346fd59ba
|
2339 2340 2341 |
{ return seq_open(filp, &kprobes_seq_ops); } |
828c09509
|
2342 |
static const struct file_operations debugfs_kprobes_operations = { |
346fd59ba
|
2343 2344 2345 2346 2347 |
.open = kprobes_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; |
637247403
|
2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 |
/* kprobes/blacklist -- shows which functions can not be probed */ static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos) { return seq_list_start(&kprobe_blacklist, *pos); } static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos) { return seq_list_next(v, &kprobe_blacklist, pos); } static int kprobe_blacklist_seq_show(struct seq_file *m, void *v) { struct kprobe_blacklist_entry *ent = list_entry(v, struct kprobe_blacklist_entry, list); |
ffb9bd68e
|
2363 2364 2365 2366 |
/* * If /proc/kallsyms is not showing kernel address, we won't * show them here either. */ |
e5541c634
|
2367 |
if (!kallsyms_show_value(m->file->f_cred)) |
ffb9bd68e
|
2368 2369 2370 2371 2372 2373 2374 |
seq_printf(m, "0x%px-0x%px\t%ps ", NULL, NULL, (void *)ent->start_addr); else seq_printf(m, "0x%px-0x%px\t%ps ", (void *)ent->start_addr, (void *)ent->end_addr, (void *)ent->start_addr); |
637247403
|
2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 |
return 0; } static const struct seq_operations kprobe_blacklist_seq_ops = { .start = kprobe_blacklist_seq_start, .next = kprobe_blacklist_seq_next, .stop = kprobe_seq_stop, /* Reuse void function */ .show = kprobe_blacklist_seq_show, }; static int kprobe_blacklist_open(struct inode *inode, struct file *filp) { return seq_open(filp, &kprobe_blacklist_seq_ops); } static const struct file_operations debugfs_kprobe_blacklist_ops = { .open = kprobe_blacklist_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; |
12310e343
|
2396 |
static int arm_all_kprobes(void) |
bf8f6e5b3
|
2397 2398 |
{ struct hlist_head *head; |
bf8f6e5b3
|
2399 |
struct kprobe *p; |
12310e343
|
2400 2401 |
unsigned int i, total = 0, errors = 0; int err, ret = 0; |
bf8f6e5b3
|
2402 2403 |
mutex_lock(&kprobe_mutex); |
e579abeb5
|
2404 2405 |
/* If kprobes are armed, just return */ if (!kprobes_all_disarmed) |
bf8f6e5b3
|
2406 |
goto already_enabled; |
977ad481b
|
2407 2408 2409 2410 2411 2412 |
/* * optimize_kprobe() called by arm_kprobe() checks * kprobes_all_disarmed, so set kprobes_all_disarmed before * arm_kprobe. */ kprobes_all_disarmed = false; |
afd66255b
|
2413 |
/* Arming kprobes doesn't optimize kprobe itself */ |
bf8f6e5b3
|
2414 2415 |
for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; |
12310e343
|
2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 |
/* Arm all kprobes on a best-effort basis */ hlist_for_each_entry_rcu(p, head, hlist) { if (!kprobe_disabled(p)) { err = arm_kprobe(p); if (err) { errors++; ret = err; } total++; } } |
bf8f6e5b3
|
2427 |
} |
12310e343
|
2428 2429 2430 2431 2432 2433 2434 |
if (errors) pr_warn("Kprobes globally enabled, but failed to arm %d out of %d probes ", errors, total); else pr_info("Kprobes globally enabled "); |
bf8f6e5b3
|
2435 2436 2437 |
already_enabled: mutex_unlock(&kprobe_mutex); |
12310e343
|
2438 |
return ret; |
bf8f6e5b3
|
2439 |
} |
297f9233b
|
2440 |
static int disarm_all_kprobes(void) |
bf8f6e5b3
|
2441 2442 |
{ struct hlist_head *head; |
bf8f6e5b3
|
2443 |
struct kprobe *p; |
297f9233b
|
2444 2445 |
unsigned int i, total = 0, errors = 0; int err, ret = 0; |
bf8f6e5b3
|
2446 2447 |
mutex_lock(&kprobe_mutex); |
e579abeb5
|
2448 |
/* If kprobes are already disarmed, just return */ |
6274de498
|
2449 2450 |
if (kprobes_all_disarmed) { mutex_unlock(&kprobe_mutex); |
297f9233b
|
2451 |
return 0; |
6274de498
|
2452 |
} |
bf8f6e5b3
|
2453 |
|
e579abeb5
|
2454 |
kprobes_all_disarmed = true; |
afd66255b
|
2455 |
|
bf8f6e5b3
|
2456 2457 |
for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; |
297f9233b
|
2458 |
/* Disarm all kprobes on a best-effort basis */ |
b67bfe0d4
|
2459 |
hlist_for_each_entry_rcu(p, head, hlist) { |
297f9233b
|
2460 2461 2462 2463 2464 2465 2466 2467 |
if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) { err = disarm_kprobe(p, false); if (err) { errors++; ret = err; } total++; } |
bf8f6e5b3
|
2468 2469 |
} } |
297f9233b
|
2470 2471 2472 2473 2474 2475 2476 2477 |
if (errors) pr_warn("Kprobes globally disabled, but failed to disarm %d out of %d probes ", errors, total); else pr_info("Kprobes globally disabled "); |
bf8f6e5b3
|
2478 |
mutex_unlock(&kprobe_mutex); |
bf8f6e5b3
|
2479 |
|
6274de498
|
2480 2481 |
/* Wait for disarming all kprobes by optimizer */ wait_for_kprobe_optimizer(); |
297f9233b
|
2482 2483 |
return ret; |
bf8f6e5b3
|
2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 |
} /* * XXX: The debugfs bool file interface doesn't allow for callbacks * when the bool state is switched. We can reuse that facility when * available */ static ssize_t read_enabled_file_bool(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { char buf[3]; |
e579abeb5
|
2495 |
if (!kprobes_all_disarmed) |
bf8f6e5b3
|
2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 |
buf[0] = '1'; else buf[0] = '0'; buf[1] = ' '; buf[2] = 0x00; return simple_read_from_buffer(user_buf, count, ppos, buf, 2); } static ssize_t write_enabled_file_bool(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos) { char buf[32]; |
efeb156e7
|
2509 |
size_t buf_size; |
12310e343
|
2510 |
int ret = 0; |
bf8f6e5b3
|
2511 2512 2513 2514 |
buf_size = min(count, (sizeof(buf)-1)); if (copy_from_user(buf, user_buf, buf_size)) return -EFAULT; |
10fb46d5f
|
2515 |
buf[buf_size] = '\0'; |
bf8f6e5b3
|
2516 2517 2518 2519 |
switch (buf[0]) { case 'y': case 'Y': case '1': |
12310e343
|
2520 |
ret = arm_all_kprobes(); |
bf8f6e5b3
|
2521 2522 2523 2524 |
break; case 'n': case 'N': case '0': |
297f9233b
|
2525 |
ret = disarm_all_kprobes(); |
bf8f6e5b3
|
2526 |
break; |
10fb46d5f
|
2527 2528 |
default: return -EINVAL; |
bf8f6e5b3
|
2529 |
} |
12310e343
|
2530 2531 |
if (ret) return ret; |
bf8f6e5b3
|
2532 2533 |
return count; } |
828c09509
|
2534 |
static const struct file_operations fops_kp = { |
bf8f6e5b3
|
2535 2536 |
.read = read_enabled_file_bool, .write = write_enabled_file_bool, |
6038f373a
|
2537 |
.llseek = default_llseek, |
bf8f6e5b3
|
2538 |
}; |
55479f647
|
2539 |
static int __init debugfs_kprobe_init(void) |
346fd59ba
|
2540 |
{ |
8c0fd1fa6
|
2541 |
struct dentry *dir; |
bf8f6e5b3
|
2542 |
unsigned int value = 1; |
346fd59ba
|
2543 2544 |
dir = debugfs_create_dir("kprobes", NULL); |
346fd59ba
|
2545 |
|
8c0fd1fa6
|
2546 2547 |
debugfs_create_file("list", 0400, dir, NULL, &debugfs_kprobes_operations); |
346fd59ba
|
2548 |
|
8c0fd1fa6
|
2549 |
debugfs_create_file("enabled", 0600, dir, &value, &fops_kp); |
637247403
|
2550 |
|
8c0fd1fa6
|
2551 2552 |
debugfs_create_file("blacklist", 0400, dir, NULL, &debugfs_kprobe_blacklist_ops); |
bf8f6e5b3
|
2553 |
|
346fd59ba
|
2554 2555 2556 2557 2558 |
return 0; } late_initcall(debugfs_kprobe_init); #endif /* CONFIG_DEBUG_FS */ |