From b2421a196cb0911ea95aec1050a0b830464c8fa6 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Sun, 24 Apr 2022 21:59:45 +0100 Subject: [PATCH] ALSA: pcm: Check for null pointer of pointer substream before dereferencing it commit 011b559be832194f992f73d6c0d5485f5925a10b upstream. 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: d4cfb30fce03 ("ALSA: pcm: Set per-card upper limit of PCM buffer allocations") Signed-off-by: Colin Ian King Link: https://lore.kernel.org/r/20220424205945.1372247-1-colin.i.king@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- 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 d360655e5deb..b961a30c2a22 100644 --- a/sound/core/pcm_memory.c +++ b/sound/core/pcm_memory.c @@ -401,7 +401,6 @@ 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)) @@ -410,6 +409,8 @@ 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);