Commit 011b559b authored Apr 24, 2022 by Colin Ian King Committed by Takashi Iwai Apr 25, 2022

ALSA: pcm: Check for null pointer of pointer substream before dereferencing it

Pointer substream is being dereferenced on the assignment of pointer card
before substream is being null checked with the macro PCM_RUNTIME_CHECK.
Although PCM_RUNTIME_CHECK calls BUG_ON, it still is useful to perform the
the pointer check before card is assigned.

Fixes: d4cfb30f ("ALSA: pcm: Set per-card upper limit of PCM buffer allocations")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220424205945.1372247-1-colin.i.king@gmail.com

Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent c92b576a

sound/core/pcm_memory.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -453,7 +453,6 @@ EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
		*/
		int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
		{
		struct snd_card *card = substream->pcm->card;
		struct snd_pcm_runtime *runtime;

		if (PCM_RUNTIME_CHECK(substream))
		@@ -462,6 +461,8 @@ int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
		if (runtime->dma_area == NULL)
		return 0;
		if (runtime->dma_buffer_p != &substream->dma_buffer) {
		struct snd_card *card = substream->pcm->card;

		/* it's a newly allocated buffer. release it now. */
		do_free_pages(card, runtime->dma_buffer_p);
		kfree(runtime->dma_buffer_p);