The patch titled
Subject: kernel/panic.c: turn off locks debug before releasing console lock
has been added to the -mm tree. Its filename is
panic-turn-off-locks-debug-before-releasing-console-lock.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/panic-turn-off-locks-debug-before-releasing-console-lock.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/panic-turn-off-locks-debug-before-releasing-console-lock.patch
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------------------------------------------------------
From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Subject: kernel/panic.c: turn off locks debug before releasing console lock
Commit 08d78658f393 ("panic: release stale console lock to always get the
logbuf printed out") introduced an unwanted bad unlock balance report when
panic() is called directly and not from OOPS (e.g. from out_of_memory()).
The difference is that in case of OOPS we disable locks debug in
oops_enter() and on direct panic call nobody does that.
Fixes: 08d78658f393 ("panic: release stale console lock to always get the logbuf printed out")
Reported-by: kernel test robot <ying.huang@xxxxxxxxxxxxxxx>
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Cc: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Xie XiuQi <xiexiuqi@xxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/panic.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff -puN kernel/panic.c~panic-turn-off-locks-debug-before-releasing-console-lock kernel/panic.c
--- a/kernel/panic.c~panic-turn-off-locks-debug-before-releasing-console-lock
+++ a/kernel/panic.c
@@ -152,8 +152,11 @@ void panic(const char *fmt, ...)
* We may have ended up stopping the CPU holding the lock (in
* smp_send_stop()) while still having some valuable data in the console
* buffer. Try to acquire the lock then release it regardless of the
- * result. The release will also print the buffers out.
+ * result. The release will also print the buffers out. Locks debug
+ * should be disabled to avoid reporting bad unlock balance when
+ * panic() is not being callled from OOPS.
*/
+ debug_locks_off();
console_trylock();
console_unlock();
_
Patches currently in -mm which might be from vkuznets@xxxxxxxxxx are
panic-turn-off-locks-debug-before-releasing-console-lock.patch
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