This is a note to let you know that I've just added the patch titled
spi: Ensure that sg_table won't be used after being freed
to the 5.10-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:
spi-ensure-that-sg_table-won-t-be-used-after-being-f.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cb6afcf302c852b61db7a99dce9f901bd9588708
Author: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Date: Fri Sep 30 13:34:08 2022 +0200
spi: Ensure that sg_table won't be used after being freed
[ Upstream commit 8e9204cddcc3fea9affcfa411715ba4f66e97587 ]
SPI code checks for non-zero sgt->orig_nents to determine if the buffer
has been DMA-mapped. Ensure that sg_table is really zeroed after free to
avoid potential NULL pointer dereference if the given SPI xfer object is
reused again without being DMA-mapped.
Fixes: 0c17ba73c08f ("spi: Fix cache corruption due to DMA/PIO overlap")
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220930113408.19720-1-m.szyprowski@xxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6ea7b286c80c..857a1399850c 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -946,6 +946,8 @@ void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
if (sgt->orig_nents) {
dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
sg_free_table(sgt);
+ sgt->orig_nents = 0;
+ sgt->nents = 0;
}
}
