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: commit d4cfb30fce03 ("ALSA: pcm: Set per-card upper limit of PCM buffer allocations")

Signed-off-by: Colin Ian King colin.i.king@gmail.com --- sound/core/pcm_memory.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c index 8848d2f3160d..b8296b6eb2c1 100644 --- a/sound/core/pcm_memory.c +++ b/sound/core/pcm_memory.c @@ -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);