This is a note to let you know that I've just added the patch titled
dma-mapping: clear dev->dma_mem to NULL after freeing it
to the 4.19-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:
dma-mapping-clear-dev-dma_mem-to-null-after-freeing-.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 06f5be69b93f9bd33ca27c10a7f7253b94dc8d49
Author: Joakim Zhang <joakim.zhang@xxxxxxxxxxx>
Date: Thu Dec 14 16:25:26 2023 +0800
dma-mapping: clear dev->dma_mem to NULL after freeing it
[ Upstream commit b07bc2347672cc8c7293c64499f1488278c5ca3d ]
Reproduced with below sequence:
dma_declare_coherent_memory()->dma_release_coherent_memory()
->dma_declare_coherent_memory()->"return -EBUSY" error
It will return -EBUSY from the dma_assign_coherent_memory()
in dma_declare_coherent_memory(), the reason is that dev->dma_mem
pointer has not been set to NULL after it's freed.
Fixes: cf65a0f6f6ff ("dma-mapping: move all DMA mapping code to kernel/dma")
Signed-off-by: Joakim Zhang <joakim.zhang@xxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/dma/coherent.c b/kernel/dma/coherent.c
index 597d40893862..4c7ffd094a57 100644
--- a/kernel/dma/coherent.c
+++ b/kernel/dma/coherent.c
@@ -369,8 +369,10 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
static void rmem_dma_device_release(struct reserved_mem *rmem,
struct device *dev)
{
- if (dev)
+ if (dev) {
dev->dma_mem = NULL;
+ dev->dma_mem = NULL;
+ }
}
static const struct reserved_mem_ops rmem_dma_ops = {
