diff options
Diffstat (limited to 'lib/spinlock_debug.c')
| -rw-r--r-- | lib/spinlock_debug.c | 53 |
1 files changed, 29 insertions, 24 deletions
diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c index 4755b98b6dfb..0374a596cffa 100644 --- a/lib/spinlock_debug.c +++ b/lib/spinlock_debug.c @@ -11,7 +11,7 @@ #include <linux/interrupt.h> #include <linux/debug_locks.h> #include <linux/delay.h> -#include <linux/module.h> +#include <linux/export.h> void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name, struct lock_class_key *key) @@ -49,19 +49,16 @@ void __rwlock_init(rwlock_t *lock, const char *name, EXPORT_SYMBOL(__rwlock_init); -static void spin_bug(raw_spinlock_t *lock, const char *msg) +static void spin_dump(raw_spinlock_t *lock, const char *msg) { struct task_struct *owner = NULL; - if (!debug_locks_off()) - return; - if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT) owner = lock->owner; printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n", msg, raw_smp_processor_id(), current->comm, task_pid_nr(current)); - printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, " + printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, " ".owner_cpu: %d\n", lock, lock->magic, owner ? owner->comm : "<none>", @@ -70,6 +67,14 @@ static void spin_bug(raw_spinlock_t *lock, const char *msg) dump_stack(); } +static void spin_bug(raw_spinlock_t *lock, const char *msg) +{ + if (!debug_locks_off()) + return; + + spin_dump(lock, msg); +} + #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg) static inline void @@ -102,27 +107,27 @@ static void __spin_lock_debug(raw_spinlock_t *lock) { u64 i; u64 loops = loops_per_jiffy * HZ; - int print_once = 1; - for (;;) { - for (i = 0; i < loops; i++) { - if (arch_spin_trylock(&lock->raw_lock)) - return; - __delay(1); - } - /* lockup suspected: */ - if (print_once) { - print_once = 0; - printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, " - "%s/%d, %p\n", - raw_smp_processor_id(), current->comm, - task_pid_nr(current), lock); - dump_stack(); + for (i = 0; i < loops; i++) { + if (arch_spin_trylock(&lock->raw_lock)) + return; + __delay(1); + } + /* lockup suspected: */ + spin_dump(lock, "lockup suspected"); #ifdef CONFIG_SMP - trigger_all_cpu_backtrace(); + trigger_all_cpu_backtrace(); #endif - } - } + + /* + * The trylock above was causing a livelock. Give the lower level arch + * specific lock code a chance to acquire the lock. We have already + * printed a warning/backtrace at this point. The non-debug arch + * specific code might actually succeed in acquiring the lock. If it is + * not successful, the end-result is the same - there is no forward + * progress. + */ + arch_spin_lock(&lock->raw_lock); } void do_raw_spin_lock(raw_spinlock_t *lock) |