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ASoC: soc-pcm: Move debugfs removal out of spinlock

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The recent fix for DPCM locking also covered the loop in
dpcm_be_disconnect() with the FE stream lock.  This caused an
unexpected side effect, thought: calling debugfs_remove_recursive() in
the spinlock may lead to lockdep splats as the code there assumes the
SOFTIRQ-safe context.

For avoiding the problem, this patch changes the disconnection
procedure to two phases: at first, the matching entries are removed
from the linked list, then the resources are freed outside the lock.

Fixes: b7898396f4bb ("ASoC: soc-pcm: Fix and cleanup DPCM locking")
Reported-and-tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20220119155249.26754-3-tiwai@suse.de
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Takashi Iwai 2022-01-19 16:52:49 +01:00 committed by Mark Brown
parent 3c75c0ea5d
commit 9f620684c1
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 10 additions and 4 deletions
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14
sound/soc/soc-pcm.c
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@ -1268,6 +1268,7 @@ static void dpcm_be_reparent(struct snd_soc_pcm_runtime *fe,
void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
{
struct snd_soc_dpcm *dpcm, *d;
LIST_HEAD(deleted_dpcms);
snd_soc_dpcm_mutex_assert_held(fe);
@ -1287,13 +1288,18 @@ void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
/* BEs still alive need new FE */
dpcm_be_reparent(fe, dpcm->be, stream);
dpcm_remove_debugfs_state(dpcm);
list_del(&dpcm->list_be);
list_del(&dpcm->list_fe);
kfree(dpcm);
list_move(&dpcm->list_fe, &deleted_dpcms);
}
snd_soc_dpcm_stream_unlock_irq(fe, stream);
while (!list_empty(&deleted_dpcms)) {
dpcm = list_first_entry(&deleted_dpcms, struct snd_soc_dpcm,
list_fe);
list_del(&dpcm->list_fe);
dpcm_remove_debugfs_state(dpcm);
kfree(dpcm);
}
}
/* get BE for DAI widget and stream */