On 03 Dec 2020 07:33:03 +0900, Kuninori Morimoto wrote:
>Hi Gyeongtaek
>
>Thank you for your patch
>
>> If stop by underrun and DPCM BE disconnection is run simultaneously,
>> data abort can be occurred by the sequence below.
>>
>> /* In core X, running dpcm_be_dai_trigger() */
>> for_each_dpcm_be(fe, stream, dpcm) {
>> /* In core Y, running dpcm_be_disconnect() */
>> spin_lock_irqsave(&fe->card->dpcm_lock, flags);
>> list_del(&dpcm->list_be);
>> list_del(&dpcm->list_fe);
>> spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
>> kfree(dpcm);
>> /* In core X, running dpcm_be_dai_trigger() */
>> struct snd_soc_pcm_runtime *be = dpcm->be; <== Accessing freed memory
>
>It is easy to read/understand if this code has alignment.
>
>> To prevent this situation, dpcm_lock should be acquired during
>> iteration of dpcm list in dpcm_do_trigger().
>>
>> Signed-off-by: Gyeongtaek Lee <gt82.lee@xxxxxxxxxxx>
>> Cc: stable@xxxxxxxxxxxxxxx
>> ---
>
>Is this bugfix patch for some recent commit ?
>If so, having Fixes: tag is helpful.
>
>Thank you for your help !!
I tried to find out some change from the history.
However, I saw that dpcm_lock never be held in dpcm_be_dai_trigger() from the beginning.
So, I just fixed some miss from the commit comment and resend.
If you have another suggestion or request, just let me know.
And I have a question.
This patch can’t be applied to stable branches directly by conflict.
I found out following commits are needed to apply this patch into the 5.4 stable.
ASoC: soc-pcm: remove snd_soc_dpcm_be_get/set_state()
ASoC: soc-pcm: add snd_soc_dpcm_can_be() and remove duplicate code
In this case, what should I do when stable maintainer requests resolving conflict to me?
Should I send those patches to the maintainer?
Or rewrite the patch on the latest of the each stable?
Thank you!
Gyeongtaek Lee
>
>Best regards
>---
>Kuninori Morimoto
>
Gyeongtaek Lee (1):
ASoC: dpcm: acquire dpcm_lock in dpcm_do_trigger()
sound/soc/soc-pcm.c | 62 ++++++++++++++++++++++++++++++++-------------
1 file changed, 44 insertions(+), 18 deletions(-)
base-commit: fa02fcd94b0c8dff6cc65714510cf25ad194b90d
--
2.21.0
