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| author | Takashi Iwai <tiwai@suse.de> | 2020-02-14 12:13:15 +0100 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2020-02-14 15:53:09 +0100 |
| commit | dc7497795e014d84699c3b8809ed6df35352dd74 (patch) | |
| tree | 2268c9c6fe20d5638e558ae014d512b85e543599 /sound/core/seq/seq_clientmgr.c | |
| parent | ALSA: seq: Avoid concurrent access to queue flags (diff) | |
| download | linux-dc7497795e014d84699c3b8809ed6df35352dd74.tar.xz linux-dc7497795e014d84699c3b8809ed6df35352dd74.zip | |
ALSA: seq: Fix concurrent access to queue current tick/time
snd_seq_check_queue() passes the current tick and time of the given
queue as a pointer to snd_seq_prioq_cell_out(), but those might be
updated concurrently by the seq timer update.
Fix it by retrieving the current tick and time via the proper helper
functions at first, and pass those values to snd_seq_prioq_cell_out()
later in the loops.
snd_seq_timer_get_cur_time() takes a new argument and adjusts with the
current system time only when it's requested so; this update isn't
needed for snd_seq_check_queue(), as it's called either from the
interrupt handler or right after queuing.
Also, snd_seq_timer_get_cur_tick() is changed to read the value in the
spinlock for the concurrency, too.
Reported-by: syzbot+fd5e0eaa1a32999173b2@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20200214111316.26939-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/seq/seq_clientmgr.c')
| -rw-r--r-- | sound/core/seq/seq_clientmgr.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index 6d9592f0ae1d..cc93157fa950 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -580,7 +580,7 @@ static int update_timestamp_of_queue(struct snd_seq_event *event, event->queue = queue; event->flags &= ~SNDRV_SEQ_TIME_STAMP_MASK; if (real_time) { - event->time.time = snd_seq_timer_get_cur_time(q->timer); + event->time.time = snd_seq_timer_get_cur_time(q->timer, true); event->flags |= SNDRV_SEQ_TIME_STAMP_REAL; } else { event->time.tick = snd_seq_timer_get_cur_tick(q->timer); @@ -1659,7 +1659,7 @@ static int snd_seq_ioctl_get_queue_status(struct snd_seq_client *client, tmr = queue->timer; status->events = queue->tickq->cells + queue->timeq->cells; - status->time = snd_seq_timer_get_cur_time(tmr); + status->time = snd_seq_timer_get_cur_time(tmr, true); status->tick = snd_seq_timer_get_cur_tick(tmr); status->running = tmr->running; |