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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_timer.h | |
| parent | ALSA: seq: Avoid concurrent access to queue flags (diff) | |
| download | linux-dev-dc7497795e014d84699c3b8809ed6df35352dd74.tar.xz linux-dev-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 '')
| -rw-r--r-- | sound/core/seq/seq_timer.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/sound/core/seq/seq_timer.h b/sound/core/seq/seq_timer.h index 66c3e344eae3..4bec57df8158 100644 --- a/sound/core/seq/seq_timer.h +++ b/sound/core/seq/seq_timer.h @@ -120,7 +120,8 @@ int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq); int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr, snd_seq_tick_time_t position); int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr, snd_seq_real_time_t position); int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew, unsigned int base); -snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr); +snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr, + bool adjust_ktime); snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr); extern int seq_default_timer_class; |