5.4-stable review patch. If anyone has any objections, please let me know.
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From: Colin Ian King colin.i.king@gmail.com
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 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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- sound/core/pcm_memory.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- 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_pc 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);