From: Takashi Sakamoto o-takashi@sakamocchi.jp
commit 747d1f076de5a60770011f6e512de43298ec64cb upstream.
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 Link: https://lore.kernel.org/r/20200113085719.26788-1-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- sound/firewire/tascam/amdtp-tascam.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/sound/firewire/tascam/amdtp-tascam.c +++ b/sound/firewire/tascam/amdtp-tascam.c @@ -157,14 +157,15 @@ static void read_status_messages(struct 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); }