mutex: Fix w/w mutex deadlock injection
authorMaarten Lankhorst <maarten.lankhorst@canonical.com>
Tue, 30 Jul 2013 08:13:41 +0000 (10:13 +0200)
committerIngo Molnar <mingo@kernel.org>
Tue, 30 Jul 2013 20:16:40 +0000 (22:16 +0200)
commit85f4896123d0299128f2c95cc40f3b8b01d4b0f6
treecadd786200b218479e020386c4aa77cdd15688e5
parent36f571e9ed0419e73d127e18aa8992ced867268c
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>
kernel/mutex.c