Currently the SB8 MIDI code sets up the timer object at each time before scheduling it at trigger callback, but basically this is superfluous once after set up. Also, the code misses the del_timer_sync() call that may leave a race condition for use-after-free. This patch addresses these issues, moving timer_setup() to snd_sb8dsp_midi(), and adding the del_timer_sync() call at snd_sb8dsp_midi_output_trigger() to make sure. Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/isa/sb/sb8_midi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sound/isa/sb/sb8_midi.c b/sound/isa/sb/sb8_midi.c index 05ba2c6b1a8c..4affdcb78f72 100644 --- a/sound/isa/sb/sb8_midi.c +++ b/sound/isa/sb/sb8_midi.c @@ -138,6 +138,7 @@ static int snd_sb8dsp_midi_output_close(struct snd_rawmidi_substream *substream) struct snd_sb *chip; chip = substream->rmidi->private_data; + del_timer_sync(&chip->midi_timer); spin_lock_irqsave(&chip->open_lock, flags); chip->open &= ~(SB_OPEN_MIDI_OUTPUT | SB_OPEN_MIDI_OUTPUT_TRIGGER); chip->midi_substream_output = NULL; @@ -230,8 +231,6 @@ static void snd_sb8dsp_midi_output_trigger(struct snd_rawmidi_substream *substre spin_lock_irqsave(&chip->open_lock, flags); if (up) { if (!(chip->open & SB_OPEN_MIDI_OUTPUT_TRIGGER)) { - timer_setup(&chip->midi_timer, - snd_sb8dsp_midi_output_timer, 0); mod_timer(&chip->midi_timer, 1 + jiffies); chip->open |= SB_OPEN_MIDI_OUTPUT_TRIGGER; } @@ -274,6 +273,7 @@ int snd_sb8dsp_midi(struct snd_sb *chip, int device) if (chip->hardware >= SB_HW_20) rmidi->info_flags |= SNDRV_RAWMIDI_INFO_DUPLEX; rmidi->private_data = chip; + timer_setup(&chip->midi_timer, snd_sb8dsp_midi_output_timer, 0); chip->rmidi = rmidi; return 0; } -- 2.14.2