From: Takashi Iwai tiwai@suse.de
commit 8e537d5dec34cac746dd6abf6a83e5de3aa471fc upstream.
The recent refactoring of mmap handling caused Oops on some devices that don't use the standard memory allocations. This patch addresses it by allowing snd_dma_buffer_mmap() helper to receive the NULL pointer dmab argument (and return an error appropriately).
Fixes: a202bd1ad86d ("ALSA: core: Move mmap handler into memalloc ops") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20211107163911.13534-1-tiwai@suse.de Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- sound/core/memalloc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/sound/core/memalloc.c +++ b/sound/core/memalloc.c @@ -135,8 +135,11 @@ EXPORT_SYMBOL(snd_dma_free_pages); int snd_dma_buffer_mmap(struct snd_dma_buffer *dmab, struct vm_area_struct *area) { - const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab); + const struct snd_malloc_ops *ops;
+ if (!dmab) + return -ENOENT; + ops = snd_dma_get_ops(dmab); if (ops && ops->mmap) return ops->mmap(dmab, area); else