Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'locking-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Thomas Gleixner:
"Two locking fixes:
- Invoke the lockdep tracepoints in the correct place so the ordering
is correct again
- Don't leave the mutex WAITER bit stale when the last waiter is
dropping out early due to a signal as that forces all subsequent
lock operations needlessly into the slowpath until it's cleaned up
again"
* tag 'locking-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/mutex: clear MUTEX_FLAGS if wait_list is empty due to signal
locking/lockdep: Correct calling tracepoints
+19
-13
+2
-2
kernel/locking/lockdep.c
+2
-2
kernel/locking/lockdep.c
···
5736
5736
{
5737
5737
unsigned long flags;
5738
5738
5739
-
trace_lock_acquired(lock, ip);
5739
+
trace_lock_contended(lock, ip);
5740
5740
5741
5741
if (unlikely(!lock_stat || !lockdep_enabled()))
5742
5742
return;
···
5754
5754
{
5755
5755
unsigned long flags;
5756
5756
5757
-
trace_lock_contended(lock, ip);
5757
+
trace_lock_acquired(lock, ip);
5758
5758
5759
5759
if (unlikely(!lock_stat || !lockdep_enabled()))
5760
5760
return;
+2
-2
kernel/locking/mutex-debug.c
+2
-2
kernel/locking/mutex-debug.c
···
57
57
task->blocked_on = waiter;
58
58
}
59
59
60
-
void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
60
+
void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
61
61
struct task_struct *task)
62
62
{
63
63
DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));
···
65
65
DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter);
66
66
task->blocked_on = NULL;
67
67
68
-
list_del_init(&waiter->list);
68
+
INIT_LIST_HEAD(&waiter->list);
69
69
waiter->task = NULL;
70
70
}
71
71
+1
-1
kernel/locking/mutex-debug.h
+1
-1
kernel/locking/mutex-debug.h
···
22
22
extern void debug_mutex_add_waiter(struct mutex *lock,
23
23
struct mutex_waiter *waiter,
24
24
struct task_struct *task);
25
-
extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
25
+
extern void debug_mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
26
26
struct task_struct *task);
27
27
extern void debug_mutex_unlock(struct mutex *lock);
28
28
extern void debug_mutex_init(struct mutex *lock, const char *name,
+13
-5
kernel/locking/mutex.c
+13
-5
kernel/locking/mutex.c
···
194
194
* Add @waiter to a given location in the lock wait_list and set the
195
195
* FLAG_WAITERS flag if it's the first waiter.
196
196
*/
197
-
static void __sched
197
+
static void
198
198
__mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
199
199
struct list_head *list)
200
200
{
···
203
203
list_add_tail(&waiter->list, list);
204
204
if (__mutex_waiter_is_first(lock, waiter))
205
205
__mutex_set_flag(lock, MUTEX_FLAG_WAITERS);
206
+
}
207
+
208
+
static void
209
+
__mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter)
210
+
{
211
+
list_del(&waiter->list);
212
+
if (likely(list_empty(&lock->wait_list)))
213
+
__mutex_clear_flag(lock, MUTEX_FLAGS);
214
+
215
+
debug_mutex_remove_waiter(lock, waiter, current);
206
216
}
207
217
208
218
/*
···
1071
1061
__ww_mutex_check_waiters(lock, ww_ctx);
1072
1062
}
1073
1063
1074
-
mutex_remove_waiter(lock, &waiter, current);
1075
-
if (likely(list_empty(&lock->wait_list)))
1076
-
__mutex_clear_flag(lock, MUTEX_FLAGS);
1064
+
__mutex_remove_waiter(lock, &waiter);
1077
1065
1078
1066
debug_mutex_free_waiter(&waiter);
1079
1067
···
1088
1080
1089
1081
err:
1090
1082
__set_current_state(TASK_RUNNING);
1091
-
mutex_remove_waiter(lock, &waiter, current);
1083
+
__mutex_remove_waiter(lock, &waiter);
1092
1084
err_early_kill:
1093
1085
spin_unlock(&lock->wait_lock);
1094
1086
debug_mutex_free_waiter(&waiter);
+1
-3
kernel/locking/mutex.h
+1
-3
kernel/locking/mutex.h
···
10
10
* !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs:
11
11
*/
12
12
13
-
#define mutex_remove_waiter(lock, waiter, task) \
14
-
__list_del((waiter)->list.prev, (waiter)->list.next)
15
-
16
13
#define debug_mutex_wake_waiter(lock, waiter) do { } while (0)
17
14
#define debug_mutex_free_waiter(waiter) do { } while (0)
18
15
#define debug_mutex_add_waiter(lock, waiter, ti) do { } while (0)
16
+
#define debug_mutex_remove_waiter(lock, waiter, ti) do { } while (0)
19
17
#define debug_mutex_unlock(lock) do { } while (0)
20
18
#define debug_mutex_init(lock, name, key) do { } while (0)
21
19