This is a note to let you know that I've just added the patch titled
ALSA: pcm: Check for null pointer of pointer substream before dereferencing it
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-pcm-check-for-null-pointer-of-pointer-substream-before-dereferencing-it.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 011b559be832194f992f73d6c0d5485f5925a10b Mon Sep 17 00:00:00 2001
From: Colin Ian King <colin.i.king@xxxxxxxxx>
Date: Sun, 24 Apr 2022 21:59:45 +0100
Subject: ALSA: pcm: Check for null pointer of pointer substream before dereferencing it
From: Colin Ian King <colin.i.king@xxxxxxxxx>
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@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220424205945.1372247-1-colin.i.king@xxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
Patches currently in stable-queue which might be from colin.i.king@xxxxxxxxx are
queue-5.4/alsa-pcm-check-for-null-pointer-of-pointer-substream-before-dereferencing-it.patch
