ALSA: memalloc: Catch call with NULL snd_dma_buffer pointer

[ 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@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 05e3a2bcbea7d41485db68aa92fc1d5bc6c09fdc..fcb082b4e6bd3d0ee63d9624071a0f05d427bc0c 100644 (file)
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -403,6 +403,8 @@ 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;