Commit 08d78658f393 ("panic: release stale console lock to always get the
logbuf printed out") introduced 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.hu...@linux.intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
Cc: HATAYAMA Daisuke <d.hatay...@jp.fujitsu.com>
Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Cc: Jiri Kosina <jkos...@suse.cz>
Cc: Baoquan He <b...@redhat.com>
Cc: Prarit Bhargava <pra...@redhat.com>
Cc: Xie XiuQi <xiexi...@huawei.com>
Cc: Seth Jennings <sjenn...@redhat.com>
Cc: "K. Y. Srinivasan" <k...@microsoft.com>
Cc: Jan Kara <j...@suse.cz>
Cc: Petr Mladek <pmla...@suse.cz>
Cc: Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com>
---
The original plan was to replace this patch with less hackish implementation
from Jan's "printk: Softlockup avoidance" series but it seems it didn't get
merged in 4.4 so we still need some band-aid for now.
---
kernel/panic.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/panic.c b/kernel/panic.c
index 4579dbb..4b150bc 100644
--- a/kernel/panic.c
+++ b/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();
--
2.4.3
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