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| author | Takashi Iwai <tiwai@suse.de> | 2021-07-31 11:34:46 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2021-07-31 11:36:06 +0300 |
| commit | 825a52482a616d74bd2f5eacc0f8946d025499a7 (patch) | |
| tree | c9c83fbe54d3590b7f1b1b621bbc4a0bf4267cf0 /sound/core | |
| parent | fac24b0f34c179c6ca863f5205fad42a676caf9a (diff) | |
| download | linux-825a52482a616d74bd2f5eacc0f8946d025499a7.tar.xz | |
ALSA: core: Fix double calls of snd_card_free() via devres
At the transition to the devres-managed card release, we've put the
check of double-free at trigger_card_release(). But this wasn't
enough, as the code path calls snd_card_free() again, and it would
lead to the doubly snd_card_free() calls.
Actually the v1 patch was correct to handle this, but I forgot that
corner case and moved the check to the more obvious place as I thought
it's clearer. But, as usual, devils live in details.
This patch corrects the check of the double-free to the right place,
with a bit more comments.
Fixes: e8ad415b7a55 ("ALSA: core: Add managed card creation")
Link: https://lore.kernel.org/r/20210731083446.26680-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
| -rw-r--r-- | sound/core/init.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/sound/core/init.c b/sound/core/init.c index e985185ebc91..ac335f5906c6 100644 --- a/sound/core/init.c +++ b/sound/core/init.c @@ -605,6 +605,15 @@ int snd_card_free(struct snd_card *card) DECLARE_COMPLETION_ONSTACK(released); int ret; + /* The call of snd_card_free() is allowed from various code paths; + * a manual call from the driver and the call via devres_free, and + * we need to avoid double-free. Moreover, the release via devres + * may call snd_card_free() twice due to its nature, we need to have + * the check here at the beginning. + */ + if (card->releasing) + return 0; + card->release_completion = &released; ret = snd_card_free_when_closed(card); if (ret) @@ -813,10 +822,7 @@ EXPORT_SYMBOL_GPL(snd_card_add_dev_attr); static void trigger_card_free(void *data) { - struct snd_card *card = data; - - if (!card->releasing) - snd_card_free(data); + snd_card_free(data); } /** |