From: Takashi Iwai <tiwai@xxxxxxx>
commit 9f620684c1ef5a002b6622ecc7b5818e81252f48 upstream.
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@xxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Link: https://lore.kernel.org/r/20220119155249.26754-3-tiwai@xxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/soc/soc-pcm.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1289,6 +1289,7 @@ static void dpcm_be_reparent(struct snd_
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);
@@ -1308,13 +1309,18 @@ void dpcm_be_disconnect(struct snd_soc_p
/* BEs still alive need new FE */
dpcm_be_reparent(fe, dpcm->be, stream);
- dpcm_remove_debugfs_state(dpcm);
-
list_del(&dpcm->list_be);
+ 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);
}
- snd_soc_dpcm_stream_unlock_irq(fe, stream);
}
/* get BE for DAI widget and stream */
