Messages in this thread Patch in this message | | | From | Vitaly Kuznetsov <> | Subject | [PATCH] panic: turn off locks debug before releasing console lock | Date | Mon, 16 Nov 2015 19:20:14 +0100 |
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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.huang@linux.intel.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Baoquan He <bhe@redhat.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Jan Kara <jack@suse.cz> Cc: Petr Mladek <pmladek@suse.cz> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@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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