diff options
author | Alexey Khoroshilov <khoroshilov@ispras.ru> | 2015-04-18 02:53:25 +0300 |
---|---|---|
committer | Willy Tarreau <w@1wt.eu> | 2015-05-24 10:10:56 +0200 |
commit | c8412c6c97217654c7a6d9b9030f7910ca9a0b82 (patch) | |
tree | 88a475efc6adc58fcc07d2bfa8b2183229363146 /net/compat.c | |
parent | 533c1137c5ea83fcd59a0c5ec4b5e18e099677c0 (diff) |
sound/oss: fix deadlock in sequencer_ioctl(SNDCTL_SEQ_OUTOFBAND)
A deadlock can be initiated by userspace via ioctl(SNDCTL_SEQ_OUTOFBAND)
on /dev/sequencer with TMR_ECHO midi event.
In this case the control flow is:
sound_ioctl()
-> case SND_DEV_SEQ:
case SND_DEV_SEQ2:
sequencer_ioctl()
-> case SNDCTL_SEQ_OUTOFBAND:
spin_lock_irqsave(&lock,flags);
play_event();
-> case EV_TIMING:
seq_timing_event()
-> case TMR_ECHO:
seq_copy_to_input()
-> spin_lock_irqsave(&lock,flags);
It seems that spin_lock_irqsave() around play_event() is not necessary,
because the only other call location in seq_startplay() makes the call
without acquiring spinlock.
So, the patch just removes spinlocks around play_event().
By the way, it removes unreachable code in seq_timing_event(),
since (seq_mode == SEQ_2) case is handled in the beginning.
Compile tested only.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
(cherry picked from commit bc26d4d06e337ade069f33d3f4377593b24e6e36)
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'net/compat.c')
0 files changed, 0 insertions, 0 deletions