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torvaldstorvalds
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Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Ingo Molnar: "This tree fixes a boot crash in CONFIG_DEBUG_MUTEXES=y kernels, on kernels built with GCC 3.x (there are still such distros)" Side note: it's not just a fix for old gcc versions, it's also removing an incredibly broken/subtle check that LLVM had issues with, and that made no sense. * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: mutex: Avoid gcc version dependent __builtin_constant_p() usage
2 parents acda24c + b026750 commit 1c99ca4

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‎kernel/mutex.c

Lines changed: 16 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -410,7 +410,7 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock,
410410
static __always_inline int __sched
411411
__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
412412
struct lockdep_map *nest_lock, unsigned long ip,
413-
struct ww_acquire_ctx *ww_ctx)
413+
struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx)
414414
{
415415
struct task_struct *task = current;
416416
struct mutex_waiter waiter;
@@ -450,7 +450,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
450450
struct task_struct *owner;
451451
struct mspin_node node;
452452

453-
if (!__builtin_constant_p(ww_ctx == NULL) && ww_ctx->acquired > 0) {
453+
if (use_ww_ctx && ww_ctx->acquired > 0) {
454454
struct ww_mutex *ww;
455455

456456
ww = container_of(lock, struct ww_mutex, base);
@@ -480,7 +480,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
480480
if ((atomic_read(&lock->count) == 1) &&
481481
(atomic_cmpxchg(&lock->count, 1, 0) == 1)) {
482482
lock_acquired(&lock->dep_map, ip);
483-
if (!__builtin_constant_p(ww_ctx == NULL)) {
483+
if (use_ww_ctx) {
484484
struct ww_mutex *ww;
485485
ww = container_of(lock, struct ww_mutex, base);
486486

@@ -551,7 +551,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
551551
goto err;
552552
}
553553

554-
if (!__builtin_constant_p(ww_ctx == NULL) && ww_ctx->acquired > 0) {
554+
if (use_ww_ctx && ww_ctx->acquired > 0) {
555555
ret = __mutex_lock_check_stamp(lock, ww_ctx);
556556
if (ret)
557557
goto err;
@@ -575,7 +575,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
575575
lock_acquired(&lock->dep_map, ip);
576576
mutex_set_owner(lock);
577577

578-
if (!__builtin_constant_p(ww_ctx == NULL)) {
578+
if (use_ww_ctx) {
579579
struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
580580
struct mutex_waiter *cur;
581581

@@ -615,7 +615,7 @@ mutex_lock_nested(struct mutex *lock, unsigned int subclass)
615615
{
616616
might_sleep();
617617
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
618-
subclass, NULL, _RET_IP_, NULL);
618+
subclass, NULL, _RET_IP_, NULL, 0);
619619
}
620620

621621
EXPORT_SYMBOL_GPL(mutex_lock_nested);
@@ -625,7 +625,7 @@ _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
625625
{
626626
might_sleep();
627627
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE,
628-
0, nest, _RET_IP_, NULL);
628+
0, nest, _RET_IP_, NULL, 0);
629629
}
630630

631631
EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
@@ -635,7 +635,7 @@ mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
635635
{
636636
might_sleep();
637637
return __mutex_lock_common(lock, TASK_KILLABLE,
638-
subclass, NULL, _RET_IP_, NULL);
638+
subclass, NULL, _RET_IP_, NULL, 0);
639639
}
640640
EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
641641

@@ -644,7 +644,7 @@ mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
644644
{
645645
might_sleep();
646646
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
647-
subclass, NULL, _RET_IP_, NULL);
647+
subclass, NULL, _RET_IP_, NULL, 0);
648648
}
649649

650650
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
@@ -682,7 +682,7 @@ __ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
682682

683683
might_sleep();
684684
ret = __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE,
685-
0, &ctx->dep_map, _RET_IP_, ctx);
685+
0, &ctx->dep_map, _RET_IP_, ctx, 1);
686686
if (!ret && ctx->acquired > 1)
687687
return ww_mutex_deadlock_injection(lock, ctx);
688688

@@ -697,7 +697,7 @@ __ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
697697

698698
might_sleep();
699699
ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE,
700-
0, &ctx->dep_map, _RET_IP_, ctx);
700+
0, &ctx->dep_map, _RET_IP_, ctx, 1);
701701

702702
if (!ret && ctx->acquired > 1)
703703
return ww_mutex_deadlock_injection(lock, ctx);
@@ -809,36 +809,36 @@ __mutex_lock_slowpath(atomic_t *lock_count)
809809
struct mutex *lock = container_of(lock_count, struct mutex, count);
810810

811811
__mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0,
812-
NULL, _RET_IP_, NULL);
812+
NULL, _RET_IP_, NULL, 0);
813813
}
814814

815815
static noinline int __sched
816816
__mutex_lock_killable_slowpath(struct mutex *lock)
817817
{
818818
return __mutex_lock_common(lock, TASK_KILLABLE, 0,
819-
NULL, _RET_IP_, NULL);
819+
NULL, _RET_IP_, NULL, 0);
820820
}
821821

822822
static noinline int __sched
823823
__mutex_lock_interruptible_slowpath(struct mutex *lock)
824824
{
825825
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0,
826-
NULL, _RET_IP_, NULL);
826+
NULL, _RET_IP_, NULL, 0);
827827
}
828828

829829
static noinline int __sched
830830
__ww_mutex_lock_slowpath(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
831831
{
832832
return __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0,
833-
NULL, _RET_IP_, ctx);
833+
NULL, _RET_IP_, ctx, 1);
834834
}
835835

836836
static noinline int __sched
837837
__ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock,
838838
struct ww_acquire_ctx *ctx)
839839
{
840840
return __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0,
841-
NULL, _RET_IP_, ctx);
841+
NULL, _RET_IP_, ctx, 1);
842842
}
843843

844844
#endif

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