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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 runtim= e in snd_pcm_drain") Signed-off-by: Ji'an Zhou --- sound/core/pcm_native.c | 7 +++---- 1 file 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 *su= bstream, drain_no_period_wakeup =3D to_check->no_period_wakeup; drain_rate =3D to_check->rate; drain_bufsz =3D 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 =3D MAX_SCHEDULE_TIMEOUT; @@ -2219,7 +2218,7 @@ static int snd_pcm_drain(struct snd_pcm_substream *su= bstream, group =3D snd_pcm_stream_group_ref(substream); snd_pcm_group_for_each_entry(s, substream) { if (s->runtime =3D=3D to_check) { - remove_wait_queue(&to_check->sleep, &wait); + finish_wait(&to_check->sleep, &wait); break; } } --=20 2.43.0