From: Andrew Morton Date: Sat, 5 Aug 2006 19:13:47 +0000 (-0700) Subject: [PATCH] disable debugging version of write_lock() X-Git-Tag: v2.6.18-rc4~40 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=72f0b4e2133ba1d65147d06016c0b6d2202235ca;p=linux-2.6 [PATCH] disable debugging version of write_lock() 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c index 3d9c4dc965..58c577dd82 100644 --- a/lib/spinlock_debug.c +++ b/lib/spinlock_debug.c @@ -162,6 +162,7 @@ static void rwlock_bug(rwlock_t *lock, const char *msg) #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; @@ -184,12 +185,12 @@ static void __read_lock_debug(rwlock_t *lock) } } } +#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) @@ -235,6 +236,7 @@ static inline void debug_write_unlock(rwlock_t *lock) lock->owner_cpu = -1; } +#if 0 /* This can cause lockups */ static void __write_lock_debug(rwlock_t *lock) { int print_once = 1; @@ -257,12 +259,12 @@ static void __write_lock_debug(rwlock_t *lock) } } } +#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); }