printk, lockdep: Disable lock debugging on zap_locks()
zap_locks() is used by printk() in a last ditch effort to get data
out, clearly we cannot trust lock state after this so make it disable
lock debugging.
Also don't treat printk recursion through lockdep as a normal
recursion bug but try hard to get the lockdep splat out.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-kqxwmo4xz37e1s8w0xopvr0q@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index b6a56e3..d36619e 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -343,6 +343,8 @@
#define lockdep_assert_held(l) WARN_ON(debug_locks && !lockdep_is_held(l))
+#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
+
#else /* !LOCKDEP */
static inline void lockdep_off(void)
@@ -392,6 +394,8 @@
#define lockdep_assert_held(l) do { } while (0)
+#define lockdep_recursing(tsk) (0)
+
#endif /* !LOCKDEP */
#ifdef CONFIG_LOCK_STAT
diff --git a/kernel/printk.c b/kernel/printk.c
index 1455a0d..6d08794 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -688,6 +688,7 @@
oops_timestamp = jiffies;
+ debug_locks_off();
/* If a crash is occurring, make sure we can't deadlock */
raw_spin_lock_init(&logbuf_lock);
/* And make sure that we print immediately */
@@ -856,7 +857,7 @@
* recursion and return - but flag the recursion so that
* it can be printed at the next appropriate moment:
*/
- if (!oops_in_progress) {
+ if (!oops_in_progress && !lockdep_recursing(current)) {
recursion_bug = 1;
goto out_restore_irqs;
}