ALSA: gus: fix null pointer dereference on pointer block

[ Upstream commit a0d21bb ] The pointer block return from snd_gf1_dma_next_block could be null, so there is a potential null pointer dereference issue. Fix this by adding a null check before dereference. Signed-off-by: Chengfeng Ye <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Takashi Iwai <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
ammarfaizi2 · Nov 24, 2021 · 3164d16 · 3164d16
1 parent 29c50db
commit 3164d16
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/sound/isa/gus/gus_dma.c b/sound/isa/gus/gus_dma.c
@@ -126,6 +126,8 @@ static void snd_gf1_dma_interrupt(struct snd_gus_card * gus)
 	}
 	block = snd_gf1_dma_next_block(gus);
 	spin_unlock(&gus->dma_lock);
+	if (!block)
+		return;
 	snd_gf1_dma_program(gus, block->addr, block->buf_addr, block->count, (unsigned short) block->cmd);
 	kfree(block);
 #if 0