This is a note to let you know that I've just added the patch titled
dma: fix call order in dmam_free_coherent
to the 6.6-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-fix-call-order-in-dmam_free_coherent.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1eef76a1aa6b827168f15fff3f6c2c7a0f38f4ad
Author: Lance Richardson <rlance@xxxxxxxxxx>
Date: Thu Jul 18 14:38:24 2024 +0000
dma: fix call order in dmam_free_coherent
[ Upstream commit 28e8b7406d3a1f5329a03aa25a43aa28e087cb20 ]
dmam_free_coherent() frees a DMA allocation, which makes the
freed vaddr available for reuse, then calls devres_destroy()
to remove and free the data structure used to track the DMA
allocation. Between the two calls, it is possible for a
concurrent task to make an allocation with the same vaddr
and add it to the devres list.
If this happens, there will be two entries in the devres list
with the same vaddr and devres_destroy() can free the wrong
entry, triggering the WARN_ON() in dmam_match.
Fix by destroying the devres entry before freeing the DMA
allocation.
Tested:
kokonut //net/encryption
http://sponge2/b9145fe6-0f72-4325-ac2f-a84d81075b03
Fixes: 9ac7849e35f7 ("devres: device resource management")
Signed-off-by: Lance Richardson <rlance@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index e323ca48f7f2a..f1d9f01b283d7 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -67,8 +67,8 @@ void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
{
struct dma_devres match_data = { size, vaddr, dma_handle };
- dma_free_coherent(dev, size, vaddr, dma_handle);
WARN_ON(devres_destroy(dev, dmam_release, dmam_match, &match_data));
+ dma_free_coherent(dev, size, vaddr, dma_handle);
}
EXPORT_SYMBOL(dmam_free_coherent);
