rtmutex: Handle deadlock detection smarter

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commit 3d5c9340d1 upstream.

Even in the case when deadlock detection is not requested by the
caller, we can detect deadlocks. Right now the code stops the lock
chain walk and keeps the waiter enqueued, even on itself. Silly not to
yell when such a scenario is detected and to keep the waiter enqueued.

Return -EDEADLK unconditionally and handle it at the call sites.

The futex calls return -EDEADLK. The non futex ones dequeue the
waiter, throw a warning and put the task into a schedule loop.

Tagged for stable as it makes the code more robust.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Brad Mouring <bmouring@ni.com>
Link: http://lkml.kernel.org/r/20140605152801.836501969@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Thomas Gleixner 2014-06-05 12:34:23 +02:00 • committed by Greg Kroah-Hartman

parent ecb22e0398

commit 2b1f3807ed

3 changed files with 38 additions and 5 deletions

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5

kernel/locking/rtmutex-debug.h

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33

kernel/locking/rtmutex.c

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5

kernel/locking/rtmutex.h

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