On Mon, Jan 18, 2016 at 07:48:16PM +0100, Christian Borntraeger wrote: > On 01/18/2016 07:32 PM, Peter Zijlstra wrote: > > On Fri, Jan 15, 2016 at 04:13:34PM +0100, Christian Borntraeger wrote: > >>> Yes, the deadlock is gone and the system is still running. > >>> After some time I had the following WARN in the logs, though. > >>> Not sure yet if that is related. > >>> > >>> [25331.763607] DEBUG_LOCKS_WARN_ON(lock->owner != current) > >>> [25331.763630] ------------[ cut here ]------------ > >>> [25331.763634] WARNING: at kernel/locking/mutex-debug.c:80 > > > >> I restarted the test with panic_on_warn. Hopefully I can get a dump to check > >> which mutex this was. > > > > Hard to reproduce warnings like this tend to point towards memory > > corruption. Someone stepped on the mutex value and tickles the sanity > > check. > > > > With lockdep and debugging enabled the mutex gets quite a bit bigger, so > > it gets more likely to be hit by 'random' corruption. > > > > The locking in seq_read() seems rather straight forward. > > I was able to reproduce. The dump shows a mutex that has an owner field, which > does not exists as a task so this all looks fishy. The good thing is, that I > can reproduce the issue within some hours. (exact same backtrace). Will add some > more debug data to get a handle where we come from. Did the owner field show to something that still looks like a task_struct? -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
