[alsa-devel] [PATCH] opl3: Fix a possible sleep-in-atomic bug in snd_opl3_find_patch
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;
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
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
participants (2)
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Clemens Ladisch
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Jia-Ju Bai