ALSA: firewire-tascam: fix corruption due to spin lock without restoration in SoftIRQ context

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: d716742243 ("ALSA: firewire-tascam: queue events for change of control surface")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200113085719.26788-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto 2020-01-13 17:57:19 +09:00 committed by Takashi Iwai
parent 7fba6aea44
commit 747d1f076d

View File

@ -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);
}