diff options
| author | Ji'an Zhou <eilaimemedsnaimel@gmail.com> | 2026-06-04 14:25:59 +0000 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2026-06-04 17:24:26 +0200 |
| commit | 88fe2e3658726cb21ff2dcf9770bf672f9b9d31b (patch) | |
| tree | c42310a7be73cf7083633816e2b22d0c8bba6ffc | |
| parent | b734412619821f3ed63ba63533f539672cb7a76d (diff) | |
ALSA: PCM: Fix wait queue list corruption in snd_pcm_drain() on linked streams
snd_pcm_drain() uses init_waitqueue_entry which does not clear
entry.prev/next, and add_wait_queue with a conditional
remove_wait_queue that is skipped when to_check is no longer
in the group after concurrent UNLINK. The orphaned wait entry
remains on the unlinked substream sleep queue. On the next
drain iteration, add_wait_queue adds the entry to a new queue
while still linked on the old one, corrupting both lists. A
subsequent wake_up dereferences NULL at the func pointer
(mapped from the spinlock at offset 0 of the misinterpreted
wait_queue_head_t), causing a kernel panic.
Replace init_waitqueue_entry/add_wait_queue/conditional
remove_wait_queue with init_wait_entry/prepare_to_wait/
finish_wait. init_wait_entry clears prev/next via
INIT_LIST_HEAD on each iteration and sets
autoremove_wake_function which auto-removes the entry on
wake-up. finish_wait safely handles both the already-removed
and still-queued cases.
Fixes: 9b1dbd69ba6f ("ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain")
Signed-off-by: Ji'an Zhou <eilaimemedsnaimel@gmail.com>
Link: https://patch.msgid.link/20260604142559.3840881-1-eilaimemedsnaimel@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
| -rw-r--r-- | sound/core/pcm_native.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index a541bb235cfa..302643c1c192 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -2199,9 +2199,8 @@ static int snd_pcm_drain(struct snd_pcm_substream *substream, drain_no_period_wakeup = to_check->no_period_wakeup; drain_rate = to_check->rate; drain_bufsz = to_check->buffer_size; - init_waitqueue_entry(&wait, current); - set_current_state(TASK_INTERRUPTIBLE); - add_wait_queue(&to_check->sleep, &wait); + init_wait_entry(&wait, 0); + prepare_to_wait(&to_check->sleep, &wait, TASK_INTERRUPTIBLE); snd_pcm_stream_unlock_irq(substream); if (drain_no_period_wakeup) tout = MAX_SCHEDULE_TIMEOUT; @@ -2219,7 +2218,7 @@ static int snd_pcm_drain(struct snd_pcm_substream *substream, group = snd_pcm_stream_group_ref(substream); snd_pcm_group_for_each_entry(s, substream) { if (s->runtime == to_check) { - remove_wait_queue(&to_check->sleep, &wait); + finish_wait(&to_check->sleep, &wait); break; } } |