diff options
| author | Nicolai Hähnle <Nicolai.Haehnle@amd.com> | 2016-12-21 19:46:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-01-14 11:14:53 +0100 |
| commit | 977625a693283dbb35b2a3f674bc0237f7347348 (patch) | |
| tree | 19262cc7c358ccd341537d3c2de14cf871feaf7f | |
| parent | c516df978df1471793aaa4809b390ecd40fa93c2 (diff) | |
locking/mutex: Initialize mutex_waiter::ww_ctx with poison when debugging
Help catch cases where mutex_lock is used directly on w/w mutexes, which
otherwise result in the w/w tasks reading uninitialized data.
Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-12-git-send-email-nhaehnle@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | include/linux/poison.h | 1 | ||||
| -rw-r--r-- | kernel/locking/mutex.c | 4 |
2 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/poison.h b/include/linux/poison.h index 51334edec506..a39540326417 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -80,6 +80,7 @@ /********** kernel/mutexes **********/ #define MUTEX_DEBUG_INIT 0x11 #define MUTEX_DEBUG_FREE 0x22 +#define MUTEX_POISON_WW_CTX ((void *) 0x500 + POISON_POINTER_DELTA) /********** lib/flex_array.c **********/ #define FLEX_ARRAY_FREE 0x6c /* for use-after-free poisoning */ diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index cd8598aa0426..935116723a3d 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -785,6 +785,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, if (!use_ww_ctx) { /* add waiting tasks to the end of the waitqueue (FIFO): */ list_add_tail(&waiter.list, &lock->wait_list); + +#ifdef CONFIG_DEBUG_MUTEXES + waiter.ww_ctx = MUTEX_POISON_WW_CTX; +#endif } else { /* Add in stamp order, waking up waiters that must back off. */ ret = __ww_mutex_add_waiter(&waiter, lock, ww_ctx); |