linux-kernel - Re: [PATCH] ASoC: soc-pcm: use GFP_ATOMIC in dpcm_create_debugfs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <bbe18490-fba4-9307-fe5f-b02c00433d07@linux.intel.com>
Date:   Mon, 17 Jan 2022 11:11:42 -0600
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Takashi Iwai <tiwai@...e.de>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     alsa-devel@...a-project.org,
        Kai Vehmanen <kai.vehmanen@...ux.intel.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        Takashi Iwai <tiwai@...e.com>, Mark Brown <broonie@...nel.org>,
        Bard Liao <yung-chuan.liao@...ux.intel.com>
Subject: Re: [PATCH] ASoC: soc-pcm: use GFP_ATOMIC in
 dpcm_create_debugfs_state()



On 1/17/22 2:49 AM, Takashi Iwai wrote:
> On Sun, 16 Jan 2022 12:18:17 +0100,
> Christophe JAILLET wrote:
>>
>> The commit below states that dpcm_be_connect() may be called from atomic
>> context. It changes a GFP_KERNEL into a GFP_ATOMIC to deal with it.
>>
>> Another memory allocation is done in dpcm_create_debugfs_state() which is
>> called by dpcm_be_connect(). Also use GFP_ATOMIC there to be consistent
>> and be compliant with atomic context.
>>
>> Fixes: d8a9c6e1f676 ("ASoC: soc-pcm: use GFP_ATOMIC for dpcm structure")
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
>> ---
>> Not clear to me how dpcm_be_connect() can be called from an atomic context,
>> though. But better safe than sorry.
> 
> I don't think this no longer valid for the very latest code.
> The commit b7898396f4bb dropped the spurious dpcm_lock spinlock, so
> the code path you touched must be always sleepable.
> 
> Similarly, the commit d8a9c6e1f676 can be reverted now.

Can we really revert d8a9c6e1f676?

We did propagate the non-atomic FE property to the BE, but if both FE
and BE are both atomic that constraint would be required, no?


> 
> thanks,
> 
> Takashi
> 
>> ---
>>  sound/soc/soc-pcm.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
>> index 7abfc48b26ca..1a536a2b9dc3 100644
>> --- a/sound/soc/soc-pcm.c
>> +++ b/sound/soc/soc-pcm.c
>> @@ -212,7 +212,7 @@ static void dpcm_create_debugfs_state(struct snd_soc_dpcm *dpcm, int stream)
>>  {
>>  	char *name;
>>  
>> -	name = kasprintf(GFP_KERNEL, "%s:%s", dpcm->be->dai_link->name,
>> +	name = kasprintf(GFP_ATOMIC, "%s:%s", dpcm->be->dai_link->name,
>>  			 stream ? "capture" : "playback");
>>  	if (name) {
>>  		dpcm->debugfs_state = debugfs_create_dir(
>> -- 
>> 2.32.0
>>