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| author | Maarten Lankhorst <maarten.lankhorst@canonical.com> | 2013-07-30 10:13:41 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-07-30 22:16:40 +0200 |
| commit | 85f4896123d0299128f2c95cc40f3b8b01d4b0f6 (patch) | |
| tree | cadd786200b218479e020386c4aa77cdd15688e5 /kernel | |
| parent | 36f571e9ed0419e73d127e18aa8992ced867268c (diff) | |
| download | linux-85f4896123d0299128f2c95cc40f3b8b01d4b0f6.tar.gz linux-85f4896123d0299128f2c95cc40f3b8b01d4b0f6.tar.bz2 linux-85f4896123d0299128f2c95cc40f3b8b01d4b0f6.zip | |
mutex: Fix w/w mutex deadlock injection
The check needs to be for > 1, because ctx->acquired is already incremented.
This will prevent ww_mutex_lock_slow from returning -EDEADLK and not locking
the mutex. It caused a lot of false gpu lockups on radeon with
CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y because a function that shouldn't be able
to return -EDEADLK did.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/51F775B5.201@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/mutex.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/mutex.c b/kernel/mutex.c index ff05f4bd86eb..a52ee7bb830d 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -686,7 +686,7 @@ __ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) might_sleep(); ret = __mutex_lock_common(&lock->base, TASK_UNINTERRUPTIBLE, 0, &ctx->dep_map, _RET_IP_, ctx); - if (!ret && ctx->acquired > 0) + if (!ret && ctx->acquired > 1) return ww_mutex_deadlock_injection(lock, ctx); return ret; @@ -702,7 +702,7 @@ __ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) ret = __mutex_lock_common(&lock->base, TASK_INTERRUPTIBLE, 0, &ctx->dep_map, _RET_IP_, ctx); - if (!ret && ctx->acquired > 0) + if (!ret && ctx->acquired > 1) return ww_mutex_deadlock_injection(lock, ctx); return ret; |