* [PATCH] opl3: Fix a possible sleep-in-atomic bug in snd_opl3_find_patch
@ 2017-10-09 2:35 Jia-Ju Bai
2017-10-09 6:32 ` [alsa-devel] " Clemens Ladisch
0 siblings, 1 reply; 3+ messages in thread
From: Jia-Ju Bai @ 2017-10-09 2:35 UTC (permalink / raw)
To: perex, tiwai, o-takashi, elfring, fabf
Cc: alsa-devel, linux-kernel, Jia-Ju Bai
The driver may sleep under a spinlock, and the function call path is:
snd_opl3_note_on (acquire the spinlock)
snd_opl3_find_patch
kzalloc(GFP_KERNEL) --> may sleep
To fix it, GFP_KERNEL is replaced with GFP_ATOMIC.
This bug is found by my static analysis tool and my code review.
Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
---
sound/drivers/opl3/opl3_synth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/drivers/opl3/opl3_synth.c b/sound/drivers/opl3/opl3_synth.c
index ddcc1a3..2e1cb2b 100644
--- a/sound/drivers/opl3/opl3_synth.c
+++ b/sound/drivers/opl3/opl3_synth.c
@@ -325,7 +325,7 @@ struct fm_patch *snd_opl3_find_patch(struct snd_opl3 *opl3, int prog, int bank,
if (!create_patch)
return NULL;
- patch = kzalloc(sizeof(*patch), GFP_KERNEL);
+ patch = kzalloc(sizeof(*patch), GFP_ATOMIC);
if (!patch)
return NULL;
patch->prog = prog;
--
1.7.9.5
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [alsa-devel] [PATCH] opl3: Fix a possible sleep-in-atomic bug in snd_opl3_find_patch
2017-10-09 2:35 [PATCH] opl3: Fix a possible sleep-in-atomic bug in snd_opl3_find_patch Jia-Ju Bai
@ 2017-10-09 6:32 ` Clemens Ladisch
2017-10-09 7:51 ` Jia-Ju Bai
0 siblings, 1 reply; 3+ messages in thread
From: Clemens Ladisch @ 2017-10-09 6:32 UTC (permalink / raw)
To: Jia-Ju Bai
Cc: perex, tiwai, o-takashi, elfring, fabf, alsa-devel, linux-kernel
Jia-Ju Bai wrote:
> The driver may sleep under a spinlock, and the function call path is:
> snd_opl3_note_on (acquire the spinlock)
> snd_opl3_find_patch
> kzalloc(GFP_KERNEL) --> may sleep
This call path is not possible because create_patch is not set.
Regards,
Clemens
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [alsa-devel] [PATCH] opl3: Fix a possible sleep-in-atomic bug in snd_opl3_find_patch
2017-10-09 6:32 ` [alsa-devel] " Clemens Ladisch
@ 2017-10-09 7:51 ` Jia-Ju Bai
0 siblings, 0 replies; 3+ messages in thread
From: Jia-Ju Bai @ 2017-10-09 7:51 UTC (permalink / raw)
To: Clemens Ladisch
Cc: perex, tiwai, o-takashi, elfring, fabf, alsa-devel, linux-kernel
Thanks for your reply :)
Yes, you are right. Sorry for this false positive.
Thanks,
Jia-Ju Bai
On 2017/10/9 14:32, Clemens Ladisch wrote:
> Jia-Ju Bai wrote:
>> The driver may sleep under a spinlock, and the function call path is:
>> snd_opl3_note_on (acquire the spinlock)
>> snd_opl3_find_patch
>> kzalloc(GFP_KERNEL) --> may sleep
> This call path is not possible because create_patch is not set.
>
>
> Regards,
> Clemens
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-10-09 7:52 UTC | newest]
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2017-10-09 2:35 [PATCH] opl3: Fix a possible sleep-in-atomic bug in snd_opl3_find_patch Jia-Ju Bai
2017-10-09 6:32 ` [alsa-devel] " Clemens Ladisch
2017-10-09 7:51 ` Jia-Ju Bai
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