This is a note to let you know that I've just added the patch titled
dmaengine: Fix a double free in dma_async_device_register
to the 5.11-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:
dmaengine-fix-a-double-free-in-dma_async_device_regi.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 3aae7d2464ebfdeea75fbbe203bc9f77847b6d53
Author: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
Date: Tue Mar 30 18:44:58 2021 -0700
dmaengine: Fix a double free in dma_async_device_register
[ Upstream commit ea45b6008f8095db0cc09ad6e03c7785c2986197 ]
In the first list_for_each_entry() macro of dma_async_device_register,
it gets the chan from list and calls __dma_async_device_channel_register
(..,chan). We can see that chan->local is allocated by alloc_percpu() and
it is freed chan->local by free_percpu(chan->local) when
__dma_async_device_channel_register() failed.
But after __dma_async_device_channel_register() failed, the caller will
goto err_out and freed the chan->local in the second time by free_percpu().
The cause of this problem is forget to set chan->local to NULL when
chan->local was freed in __dma_async_device_channel_register(). My
patch sets chan->local to NULL when the callee failed to avoid double free.
Fixes: d2fb0a0438384 ("dmaengine: break out channel registration")
Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Link: https://lore.kernel.org/r/20210331014458.3944-1-lyl2019@xxxxxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index fe6a460c4373..af3ee288bc11 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1086,6 +1086,7 @@ static int __dma_async_device_channel_register(struct dma_device *device,
kfree(chan->dev);
err_free_local:
free_percpu(chan->local);
+ chan->local = NULL;
return rc;
}
