ALSA firewire-tascam driver can bring corruption due to spin lock without restoration of IRQ flag in SoftIRQ context. This commit fixes the bug.

Cc: Scott Bahling sbahling@suse.com Cc: stable@vger.kernel.org # v4.21 Fixes: d7167422433c ("ALSA: firewire-tascam: queue events for change of control surface") Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/firewire/tascam/amdtp-tascam.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sound/firewire/tascam/amdtp-tascam.c b/sound/firewire/tascam/amdtp-tascam.c index e80bb84c43f6..f823a2ab3544 100644 --- a/sound/firewire/tascam/amdtp-tascam.c +++ b/sound/firewire/tascam/amdtp-tascam.c @@ -157,14 +157,15 @@ static void read_status_messages(struct amdtp_stream *s, if ((before ^ after) & mask) { struct snd_firewire_tascam_change *entry = &tscm->queue[tscm->push_pos]; + unsigned long flag;

- spin_lock_irq(&tscm->lock); + spin_lock_irqsave(&tscm->lock, flag); entry->index = index; entry->before = before; entry->after = after; if (++tscm->push_pos >= SND_TSCM_QUEUE_COUNT) tscm->push_pos = 0; - spin_unlock_irq(&tscm->lock); + spin_unlock_irqrestore(&tscm->lock, flag);

wake_up(&tscm->hwdep_wait); }