Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750735AbWHUSsg (ORCPT ); Mon, 21 Aug 2006 14:48:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750732AbWHUSsb (ORCPT ); Mon, 21 Aug 2006 14:48:31 -0400 Received: from cantor2.suse.de ([195.135.220.15]:46780 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1750735AbWHUSsI (ORCPT ); Mon, 21 Aug 2006 14:48:08 -0400 Date: Mon, 21 Aug 2006 11:46:32 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org, torvalds@osdl.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , akpm@osdl.org, alan@lxorguk.ukuu.org.uk, Ingo Molnar , Greg Kroah-Hartman Subject: [patch 07/20] disable debugging version of write_lock() Message-ID: <20060821184632.GH21938@kroah.com> References: <20060821183818.155091391@quad.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="disable-debugging-version-of-write_lock.patch" In-Reply-To: <20060821184527.GA21938@kroah.com> User-Agent: Mutt/1.5.12-2006-07-14 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2161 Lines: 77 -stable review patch. If anyone has any objections, please let us know. ------------------ From: Andrew Morton We've confirmed that the debug version of write_lock() can get stuck for long enough to cause NMI watchdog timeouts and hence a crash. We don't know why, yet. Disable it for now. Also disable the similar read_lock() code. Just in case. Thanks to Dave Olson for reporting and testing. Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- lib/spinlock_debug.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- linux-2.6.17.8.orig/lib/spinlock_debug.c +++ linux-2.6.17.8/lib/spinlock_debug.c @@ -137,6 +137,7 @@ static void rwlock_bug(rwlock_t *lock, c #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg) +#if 0 /* __write_lock_debug() can lock up - maybe this can too? */ static void __read_lock_debug(rwlock_t *lock) { int print_once = 1; @@ -159,12 +160,12 @@ static void __read_lock_debug(rwlock_t * } } } +#endif void _raw_read_lock(rwlock_t *lock) { RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); - if (unlikely(!__raw_read_trylock(&lock->raw_lock))) - __read_lock_debug(lock); + __raw_read_lock(&lock->raw_lock); } int _raw_read_trylock(rwlock_t *lock) @@ -210,6 +211,7 @@ static inline void debug_write_unlock(rw lock->owner_cpu = -1; } +#if 0 /* This can cause lockups */ static void __write_lock_debug(rwlock_t *lock) { int print_once = 1; @@ -232,12 +234,12 @@ static void __write_lock_debug(rwlock_t } } } +#endif void _raw_write_lock(rwlock_t *lock) { debug_write_lock_before(lock); - if (unlikely(!__raw_write_trylock(&lock->raw_lock))) - __write_lock_debug(lock); + __raw_write_lock(&lock->raw_lock); debug_write_lock_after(lock); } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/