On 03/16/15 00:10, Rabin Vincent wrote:
On Sun, Mar 15, 2015 at 11:49:07PM +0200, Matthias Bonne wrote:
So the counter is set to 1 before taking the spinlock, which I think
might cause the race. Did I miss something?
Yes, you miss the fact that __mutex_slowpath_needs_to_unlock() is 0 for
the CONFIG_DEBUG_MUTEXES case:
#ifdef CONFIG_DEBUG_MUTEXES
# include "mutex-debug.h"
# include <asm-generic/mutex-null.h>
/*
* Must be 0 for the debug case so we do not do the unlock outside of the
* wait_lock region. debug_mutex_unlock() will do the actual unlock in this
* case.
*/
# undef __mutex_slowpath_needs_to_unlock
# define __mutex_slowpath_needs_to_unlock() 0
Right, I overlooked this part. Thanks to both of you for the
clarifications.
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