Commit-ID: 94d24fc47219219b5aa23b45956cc37ee5aa5b01
Gitweb: http://git.kernel.org/tip/94d24fc47219219b5aa23b45956cc37ee5aa5b01
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Tue, 7 Jun 2011 11:17:30 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 14 Nov 2011 13:35:16 +0100
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@xxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-kqxwmo4xz37e1s8w0xopvr0q@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
include/linux/lockdep.h | 4 ++++
kernel/printk.c | 3 ++-
2 files changed, 6 insertions(+), 1 deletions(-)
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 @@ extern void lockdep_trace_alloc(gfp_t mask);
#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 @@ struct lock_class_key { };
#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 @@ static void zap_locks(void)
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 @@ asmlinkage int vprintk(const char *fmt, va_list args)
* 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;
}
--
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