Messages in this thread | | | Date | Thu, 21 Mar 2024 07:33:03 +0100 | From | Takashi Iwai <> | Subject | Re: [PATCH] ALSA: timer: fix deadlock in _snd_pcm_stream_lock_irqsave |
| |
On Thu, 21 Mar 2024 03:22:24 +0100, Edward Adam Davis wrote: > > [Syzbot reported] > swapper/2/0 just changed the state of lock: > ffff88802a304110 (&group->lock#2){..-.}-{2:2}, at: _snd_pcm_stream_lock_irqsave+0xa0/0xd0 sound/core/pcm_native.c:170 > but this lock took another, SOFTIRQ-unsafe lock in the past: > (&timer->lock){+.+.}-{2:2} > > > and interrupts could create inverse lock ordering between them. > > > other info that might help us debug this: > Possible interrupt unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(&timer->lock); > local_irq_disable(); > lock(&group->lock#2); > lock(&timer->lock); > <Interrupt> > lock(&group->lock#2); > > *** DEADLOCK *** > [Fix] > Ensure that the context interrupt state is the same before and after using the > timer->lock. > > Fixes: beb45974dd49 ("ALSA: timer: Use guard() for locking") > Reported-and-tested-by: syzbot+18840ef96e57b83b7fea@syzkaller.appspotmail.com > Signed-off-by: Edward Adam Davis <eadavis@qq.com>
This was already fixed in Linus tree commit 587d67fd929ad89801bcc429675bda90d53f6592.
thanks,
Takashi
| |