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* locking/mutex: Fix debug_mutexesPeter Zijlstra2014-04-111-10/+9
| | | | | | | | | | | | | | | debug_mutex_unlock() would bail when !debug_locks and forgets to actually unlock. Reported-by: "Michael L. Semon" <mlsemon35@gmail.com> Reported-by: "Kirill A. Shutemov" <kirill@shutemov.name> Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Fixes: 6f008e72cd11 ("locking/mutex: Fix debug checks") Tested-by: Dave Jones <davej@redhat.com> Cc: Jason Low <jason.low2@hp.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140410141559.GE13658@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/mutex: Fix debug checksPeter Zijlstra2014-03-121-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | OK, so commit: 1d8fe7dc8078 ("locking/mutexes: Unlock the mutex without the wait_lock") generates this boot warning when CONFIG_DEBUG_MUTEXES=y: WARNING: CPU: 0 PID: 139 at /usr/src/linux-2.6/kernel/locking/mutex-debug.c:82 debug_mutex_unlock+0x155/0x180() DEBUG_LOCKS_WARN_ON(lock->owner != current) And that makes sense, because as soon as we release the lock a new owner can come in... One would think that !__mutex_slowpath_needs_to_unlock() implementations suffer the same, but for DEBUG we fall back to mutex-null.h which has an unconditional 1 for that. The mutex debug code requires the mutex to be unlocked after doing the debug checks, otherwise it can find inconsistent state. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: jason.low2@hp.com Link: http://lkml.kernel.org/r/20140312122442.GB27965@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* mutexes: Give more informative mutex warning in the !lock->owner caseChuansheng Liu2013-12-171-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | When mutex debugging is enabled and an imbalanced mutex_unlock() is called, we get the following, slightly confusing warning: [ 364.208284] DEBUG_LOCKS_WARN_ON(lock->owner != current) But in that case the warning is due to an imbalanced mutex_unlock() call, and the lock->owner is NULL - so the message is misleading. So improve the message by testing for this case specifically: DEBUG_LOCKS_WARN_ON(!lock->owner) Signed-off-by: Liu, Chuansheng <chuansheng.liu@intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1386136693.3650.48.camel@cliu38-desktop-build [ Improved the changelog, changed the patch to use !lock->owner consistently. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking: Move the mutex code to kernel/locking/Peter Zijlstra2013-11-061-0/+110
Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-1ditvncg30dgbpvrz2bxfmke@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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