git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 747d1f076de5a60770011f6e512de43298ec64cb Mon Sep 17 00:00:00 2001
   2 From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
   3 Date: Mon, 13 Jan 2020 17:57:19 +0900
   4 Subject: ALSA: firewire-tascam: fix corruption due to spin lock without restoration in SoftIRQ context
   5
   6 From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
   7
   8 commit 747d1f076de5a60770011f6e512de43298ec64cb upstream.
   9
  10 ALSA firewire-tascam driver can bring corruption due to spin lock without
  11 restoration of IRQ flag in SoftIRQ context. This commit fixes the bug.
  12
  13 Cc: Scott Bahling <sbahling@suse.com>
  14 Cc: <stable@vger.kernel.org> # v4.21
  15 Fixes: d7167422433c ("ALSA: firewire-tascam: queue events for change of control surface")
  16 Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
  17 Link: https://lore.kernel.org/r/20200113085719.26788-1-o-takashi@sakamocchi.jp
  18 Signed-off-by: Takashi Iwai <tiwai@suse.de>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  20
  21 ---
  22  sound/firewire/tascam/amdtp-tascam.c |    5 +++--
  23  1 file changed, 3 insertions(+), 2 deletions(-)
  24
  25 --- a/sound/firewire/tascam/amdtp-tascam.c
  26 +++ b/sound/firewire/tascam/amdtp-tascam.c
  27 @@ -157,14 +157,15 @@ static void read_status_messages(struct
  28                         if ((before ^ after) & mask) {
  29                                 struct snd_firewire_tascam_change *entry =
  30                                                 &tscm->queue[tscm->push_pos];
  31 +                               unsigned long flag;
  32
  33 -                               spin_lock_irq(&tscm->lock);
  34 +                               spin_lock_irqsave(&tscm->lock, flag);
  35                                 entry->index = index;
  36                                 entry->before = before;
  37                                 entry->after = after;
  38                                 if (++tscm->push_pos >= SND_TSCM_QUEUE_COUNT)
  39                                         tscm->push_pos = 0;
  40 -                               spin_unlock_irq(&tscm->lock);
  41 +                               spin_unlock_irqrestore(&tscm->lock, flag);
  42
  43                                 wake_up(&tscm->hwdep_wait);
  44                         }