Commit a3dbff6e authored by Jia-Ju Bai's avatar Jia-Ju Bai Committed by Mauro Carvalho Chehab

[media] cx18: Fix a sleep-in-atomic bug in snd_cx18_pcm_hw_free

The driver may sleep under a spin lock, and the function call path is:
snd_cx18_pcm_hw_free (acquire the lock by spin_lock_irqsave)
  vfree --> may sleep

To fix it, the "substream->runtime->dma_area" is passed to a temporary
value, and mark it NULL when holding the lock. The memory is freed by
vfree through the temporary value outside the lock holding.
Signed-off-by: default avatarJia-Ju Bai <baijiaju1990@163.com>
[hans.verkuil@cisco.com: removed unnecessary 'if (dma_area)']
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent d989dc20
...@@ -257,14 +257,16 @@ static int snd_cx18_pcm_hw_free(struct snd_pcm_substream *substream) ...@@ -257,14 +257,16 @@ static int snd_cx18_pcm_hw_free(struct snd_pcm_substream *substream)
{ {
struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream); struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
unsigned long flags; unsigned long flags;
unsigned char *dma_area = NULL;
spin_lock_irqsave(&cxsc->slock, flags); spin_lock_irqsave(&cxsc->slock, flags);
if (substream->runtime->dma_area) { if (substream->runtime->dma_area) {
dprintk("freeing pcm capture region\n"); dprintk("freeing pcm capture region\n");
vfree(substream->runtime->dma_area); dma_area = substream->runtime->dma_area;
substream->runtime->dma_area = NULL; substream->runtime->dma_area = NULL;
} }
spin_unlock_irqrestore(&cxsc->slock, flags); spin_unlock_irqrestore(&cxsc->slock, flags);
vfree(dma_area);
return 0; return 0;
} }
......
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