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Commit d989dc20 authored by Jia-Ju Bai's avatar Jia-Ju Bai Committed by Mauro Carvalho Chehab
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[media] ivtv: Fix a sleep-in-atomic bug in snd_ivtv_pcm_hw_free 



The driver may sleep under a spin lock, and the function call path is:
snd_ivtv_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 dde32d41

drivers/media/pci/ivtv/ivtv-alsa-pcm.c

+3 −1
Original line number Diff line number Diff line
@@ -262,14 +262,16 @@ static int snd_ivtv_pcm_hw_free(struct snd_pcm_substream *substream) 
{

	struct snd_ivtv_card *itvsc = snd_pcm_substream_chip(substream);

	unsigned long flags;

	unsigned char *dma_area = NULL;



	spin_lock_irqsave(&itvsc->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(&itvsc->slock, flags);

	vfree(dma_area);



	return 0;

}