[PATCH 5.15 797/917] ALSA: memalloc: Catch call with NULL snd_dma_buffer pointer

[Greg Kroah-Hartman]

From: Takashi Iwai <tiwai@xxxxxxx>

[ Upstream commit dce9446192439eaac81c21f517325fb473735e53 ]

Although we've covered all calls with NULL dma buffer pointer, so far,
there may be still some else in the wild.  For catching such a case
more easily, add a WARN_ON_ONCE() in snd_dma_get_ops().

Fixes: 37af81c5998f ("ALSA: core: Abstract memory alloc helpers")
Link: https://lore.kernel.org/r/20211105102103.28148-1-tiwai@xxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 sound/core/memalloc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 0b8a1c3eae1b4..2d842982576bb 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -494,6 +494,8 @@ static const struct snd_malloc_ops *dma_ops[] = {
 
 static const struct snd_malloc_ops *snd_dma_get_ops(struct snd_dma_buffer *dmab)
 {
+	if (WARN_ON_ONCE(!dmab))
+		return NULL;
 	if (WARN_ON_ONCE(dmab->dev.type <= SNDRV_DMA_TYPE_UNKNOWN ||
 			 dmab->dev.type >= ARRAY_SIZE(dma_ops)))
 		return NULL;
-- 
2.33.0