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Commit ce2c6b53847afc444c4d0a7a1075c61f499c57a5

Authored by Thomas Gleixner
Committed by Linus Torvalds
1 parent 2b8de5f50e

[PATCH] futex: Apply recent futex fixes to futex_compat 

The recent fixups in futex.c need to be applied to futex_compat.c too.  Fixes
a hang reported by Olaf.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Olaf Hering <olh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 1 changed file with 3 additions and 3 deletions Inline Diff

kernel/futex_compat.c
Diff comments   View file @ ce2c6b5
1 /* 1 /*
2 * linux/kernel/futex_compat.c 2 * linux/kernel/futex_compat.c
3 * 3 *
4 * Futex compatibililty routines. 4 * Futex compatibililty routines.
5 * 5 *
6 * Copyright 2006, Red Hat, Inc., Ingo Molnar 6 * Copyright 2006, Red Hat, Inc., Ingo Molnar
7 */ 7 */
8 8
9 #include <linux/linkage.h> 9 #include <linux/linkage.h>
10 #include <linux/compat.h> 10 #include <linux/compat.h>
11 #include <linux/futex.h> 11 #include <linux/futex.h>
12 12
13 #include <asm/uaccess.h> 13 #include <asm/uaccess.h>
14 14
15 15
16 /* 16 /*
17 * Fetch a robust-list pointer. Bit 0 signals PI futexes: 17 * Fetch a robust-list pointer. Bit 0 signals PI futexes:
18 */ 18 */
19 static inline int 19 static inline int
20 fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry, 20 fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
21 compat_uptr_t *head, int *pi) 21 compat_uptr_t *head, int *pi)
22 { 22 {
23 if (get_user(*uentry, head)) 23 if (get_user(*uentry, head))
24 return -EFAULT; 24 return -EFAULT;
25 25
26 *entry = compat_ptr((*uentry) & ~1); 26 *entry = compat_ptr((*uentry) & ~1);
27 *pi = (unsigned int)(*uentry) & 1; 27 *pi = (unsigned int)(*uentry) & 1;
28 28
29 return 0; 29 return 0;
30 } 30 }
31 31
32 /* 32 /*
33 * Walk curr->robust_list (very carefully, it's a userspace list!) 33 * Walk curr->robust_list (very carefully, it's a userspace list!)
34 * and mark any locks found there dead, and notify any waiters. 34 * and mark any locks found there dead, and notify any waiters.
35 * 35 *
36 * We silently return on any sign of list-walking problem. 36 * We silently return on any sign of list-walking problem.
37 */ 37 */
38 void compat_exit_robust_list(struct task_struct *curr) 38 void compat_exit_robust_list(struct task_struct *curr)
39 { 39 {
40 struct compat_robust_list_head __user *head = curr->compat_robust_list; 40 struct compat_robust_list_head __user *head = curr->compat_robust_list;
41 struct robust_list __user *entry, *pending; 41 struct robust_list __user *entry, *pending;
42 unsigned int limit = ROBUST_LIST_LIMIT, pi; 42 unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
43 compat_uptr_t uentry, upending; 43 compat_uptr_t uentry, upending;
44 compat_long_t futex_offset; 44 compat_long_t futex_offset;
45 45
46 /* 46 /*
47 * Fetch the list head (which was registered earlier, via 47 * Fetch the list head (which was registered earlier, via
48 * sys_set_robust_list()): 48 * sys_set_robust_list()):
49 */ 49 */
50 if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi)) 50 if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
51 return; 51 return;
52 /* 52 /*
53 * Fetch the relative futex offset: 53 * Fetch the relative futex offset:
54 */ 54 */
55 if (get_user(futex_offset, &head->futex_offset)) 55 if (get_user(futex_offset, &head->futex_offset))
56 return; 56 return;
57 /* 57 /*
58 * Fetch any possibly pending lock-add first, and handle it 58 * Fetch any possibly pending lock-add first, and handle it
59 * if it exists: 59 * if it exists:
60 */ 60 */
61 if (fetch_robust_entry(&upending, &pending, 61 if (fetch_robust_entry(&upending, &pending,
62 &head->list_op_pending, &pi)) 62 &head->list_op_pending, &pip))
63 return; 63 return;
64 if (upending) 64 if (upending)
65 handle_futex_death((void *)pending + futex_offset, curr, pi); 65 handle_futex_death((void *)pending + futex_offset, curr, pip);
66 66
67 while (compat_ptr(uentry) != &head->list) { 67 while (compat_ptr(uentry) != &head->list) {
68 /* 68 /*
69 * A pending lock might already be on the list, so 69 * A pending lock might already be on the list, so
70 * dont process it twice: 70 * dont process it twice:
71 */ 71 */
72 if (entry != pending) 72 if (entry != pending)
73 if (handle_futex_death((void *)entry + futex_offset, 73 if (handle_futex_death((void *)entry + futex_offset,
74 curr, pi)) 74 curr, pi))
75 return; 75 return;
76 76
77 /* 77 /*
78 * Fetch the next entry in the list: 78 * Fetch the next entry in the list:
79 */ 79 */
80 if (fetch_robust_entry(&uentry, &entry, 80 if (fetch_robust_entry(&uentry, &entry,
81 (compat_uptr_t *)&entry->next, &pi)) 81 (compat_uptr_t *)&entry->next, &pi))
82 return; 82 return;
83 /* 83 /*
84 * Avoid excessively long or circular lists: 84 * Avoid excessively long or circular lists:
85 */ 85 */
86 if (!--limit) 86 if (!--limit)
87 break; 87 break;
88 88
89 cond_resched(); 89 cond_resched();
90 } 90 }
91 } 91 }
92 92
93 asmlinkage long 93 asmlinkage long
94 compat_sys_set_robust_list(struct compat_robust_list_head __user *head, 94 compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
95 compat_size_t len) 95 compat_size_t len)
96 { 96 {
97 if (unlikely(len != sizeof(*head))) 97 if (unlikely(len != sizeof(*head)))
98 return -EINVAL; 98 return -EINVAL;
99 99
100 current->compat_robust_list = head; 100 current->compat_robust_list = head;
101 101
102 return 0; 102 return 0;
103 } 103 }
104 104
105 asmlinkage long 105 asmlinkage long
106 compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr, 106 compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
107 compat_size_t __user *len_ptr) 107 compat_size_t __user *len_ptr)
108 { 108 {
109 struct compat_robust_list_head *head; 109 struct compat_robust_list_head *head;
110 unsigned long ret; 110 unsigned long ret;
111 111
112 if (!pid) 112 if (!pid)
113 head = current->compat_robust_list; 113 head = current->compat_robust_list;
114 else { 114 else {
115 struct task_struct *p; 115 struct task_struct *p;
116 116
117 ret = -ESRCH; 117 ret = -ESRCH;
118 read_lock(&tasklist_lock); 118 read_lock(&tasklist_lock);
119 p = find_task_by_pid(pid); 119 p = find_task_by_pid(pid);
120 if (!p) 120 if (!p)
121 goto err_unlock; 121 goto err_unlock;
122 ret = -EPERM; 122 ret = -EPERM;
123 if ((current->euid != p->euid) && (current->euid != p->uid) && 123 if ((current->euid != p->euid) && (current->euid != p->uid) &&
124 !capable(CAP_SYS_PTRACE)) 124 !capable(CAP_SYS_PTRACE))
125 goto err_unlock; 125 goto err_unlock;
126 head = p->compat_robust_list; 126 head = p->compat_robust_list;
127 read_unlock(&tasklist_lock); 127 read_unlock(&tasklist_lock);
128 } 128 }
129 129
130 if (put_user(sizeof(*head), len_ptr)) 130 if (put_user(sizeof(*head), len_ptr))
131 return -EFAULT; 131 return -EFAULT;
132 return put_user(ptr_to_compat(head), head_ptr); 132 return put_user(ptr_to_compat(head), head_ptr);
133 133
134 err_unlock: 134 err_unlock:
135 read_unlock(&tasklist_lock); 135 read_unlock(&tasklist_lock);
136 136
137 return ret; 137 return ret;
138 } 138 }
139 139
140 asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val, 140 asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
141 struct compat_timespec __user *utime, u32 __user *uaddr2, 141 struct compat_timespec __user *utime, u32 __user *uaddr2,
142 u32 val3) 142 u32 val3)
143 { 143 {
144 struct timespec t; 144 struct timespec t;
145 unsigned long timeout = MAX_SCHEDULE_TIMEOUT; 145 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
146 int val2 = 0; 146 int val2 = 0;
147 147
148 if (utime && (op == FUTEX_WAIT || op == FUTEX_LOCK_PI)) { 148 if (utime && (op == FUTEX_WAIT || op == FUTEX_LOCK_PI)) {
149 if (get_compat_timespec(&t, utime)) 149 if (get_compat_timespec(&t, utime))
150 return -EFAULT; 150 return -EFAULT;
151 if (!timespec_valid(&t)) 151 if (!timespec_valid(&t))
152 return -EINVAL; 152 return -EINVAL;
153 if (op == FUTEX_WAIT) 153 if (op == FUTEX_WAIT)
154 timeout = timespec_to_jiffies(&t) + 1; 154 timeout = timespec_to_jiffies(&t) + 1;
155 else { 155 else {
156 timeout = t.tv_sec; 156 timeout = t.tv_sec;
157 val2 = t.tv_nsec; 157 val2 = t.tv_nsec;
158 } 158 }
159 } 159 }
160 if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE) 160 if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE)
161 val2 = (int) (unsigned long) utime; 161 val2 = (int) (unsigned long) utime;
162 162
163 return do_futex(uaddr, op, val, timeout, uaddr2, val2, val3); 163 return do_futex(uaddr, op, val, timeout, uaddr2, val2, val3);
164 } 164 }
165 165