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: Jia-Ju Bai <baijiaju1990@xxxxxxx>
---
drivers/media/pci/cx18/cx18-alsa-pcm.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/media/pci/cx18/cx18-alsa-pcm.c b/drivers/media/pci/cx18/cx18-alsa-pcm.c
index 205a98d..8c51e4c 100644
--- a/drivers/media/pci/cx18/cx18-alsa-pcm.c
+++ b/drivers/media/pci/cx18/cx18-alsa-pcm.c
@@ -257,14 +257,17 @@ static int snd_cx18_pcm_hw_free(struct snd_pcm_substream *substream)
{
struct snd_cx18_card *cxsc = snd_pcm_substream_chip(substream);
unsigned long flags;
+ unsigned char *dma_area = NULL;
spin_lock_irqsave(&cxsc->slock, flags);
if (substream->runtime->dma_area) {
dprintk("freeing pcm capture region\n");
- vfree(substream->runtime->dma_area);
+ dma_area = substream->runtime->dma_area;
substream->runtime->dma_area = NULL;
}
spin_unlock_irqrestore(&cxsc->slock, flags);
+ if (dma_area)
+ vfree(dma_area);
return 0;
}
--
1.7.9.5
