From 0cb38295833de32e322662760cc4e23610ee49c6 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 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: ec8602556236 ("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 --- 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 8848d2f3160d8..b8296b6eb2c19 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); -- 2.39.5