diff options
| author | Ingo Molnar <mingo@elte.hu> | 2006-07-03 00:24:58 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-03 15:27:05 -0700 |
| commit | a0f1ccfd8d37457a6d8a9e01acebeefcdfcc306e (patch) | |
| tree | e16b7fe211c8ed685bed942910e2ace06e7c2e27 /kernel/printk.c | |
| parent | 3047e99ede366298c6233d1870d12a520d4d92f3 (diff) | |
| download | linux-a0f1ccfd8d37457a6d8a9e01acebeefcdfcc306e.tar.bz2 | |
[PATCH] lockdep: do not recurse in printk
Make printk()-ing from within the lock validation code safer by using the
lockdep-recursion counter.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/printk.c')
| -rw-r--r-- | kernel/printk.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/kernel/printk.c b/kernel/printk.c index 39ae24d2a415..bdba5d80496c 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -518,7 +518,9 @@ asmlinkage int vprintk(const char *fmt, va_list args) zap_locks(); /* This stops the holder of console_sem just where we want him */ - spin_lock_irqsave(&logbuf_lock, flags); + local_irq_save(flags); + lockdep_off(); + spin_lock(&logbuf_lock); printk_cpu = smp_processor_id(); /* Emit the output into the temporary buffer */ @@ -588,7 +590,7 @@ asmlinkage int vprintk(const char *fmt, va_list args) */ console_locked = 1; printk_cpu = UINT_MAX; - spin_unlock_irqrestore(&logbuf_lock, flags); + spin_unlock(&logbuf_lock); /* * Console drivers may assume that per-cpu resources have @@ -604,6 +606,8 @@ asmlinkage int vprintk(const char *fmt, va_list args) console_locked = 0; up(&console_sem); } + lockdep_on(); + local_irq_restore(flags); } else { /* * Someone else owns the drivers. We drop the spinlock, which @@ -611,7 +615,9 @@ asmlinkage int vprintk(const char *fmt, va_list args) * console drivers with the output which we just produced. */ printk_cpu = UINT_MAX; - spin_unlock_irqrestore(&logbuf_lock, flags); + spin_unlock(&logbuf_lock); + lockdep_on(); + local_irq_restore(flags); } preempt_enable(); @@ -809,8 +815,15 @@ void release_console_sem(void) console_may_schedule = 0; up(&console_sem); spin_unlock_irqrestore(&logbuf_lock, flags); - if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait)) - wake_up_interruptible(&log_wait); + if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait)) { + /* + * If we printk from within the lock dependency code, + * from within the scheduler code, then do not lock + * up due to self-recursion: + */ + if (!lockdep_internal()) + wake_up_interruptible(&log_wait); + } } EXPORT_SYMBOL(release_console_sem); |