On Mon, 29 May 2006 20:32:47 +0200 "Michal Piotrowski" <michal.k.k.piotrowski@xxxxxxxxx> wrote: > I get this with Ingo's lockdep patch from > http://people.redhat.com/mingo/generic-irq-subsystem/ > > ==================================== > [ BUG: possible deadlock detected! ] > ------------------------------------ > modprobe/592 is trying to acquire lock: > (&grp->list_mutex){----}, at: [<fd9ee555>] > snd_seq_port_connect+0xc0/0x337 [snd_seq] > > but task is already holding lock: > (&grp->list_mutex){----}, at: [<fd9ee4fb>] > snd_seq_port_connect+0x66/0x337 [snd_seq] > > which could potentially lead to deadlocks! > > other info that might help us debug this: > 1 locks held by modprobe/592: > #0: (&grp->list_mutex){----}, at: [<fd9ee4fb>] > snd_seq_port_connect+0x66/0x337 [snd_seq] yes, down_write(&src->list_mutex); down_write(&dest->list_mutex); I wonder if there's anything which prevents another task from concurrently coming in and trying to perform the opposite connection and causing a deadlock. The way we normally handle this is if (src < dest) { down_write(&src->list_mutex); down_write(&dest->list_mutex); } else { down_write(&dest->list_mutex); down_write(&src->list_mutex); } _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
