From: Marek Szyprowski Date: Fri, 30 Sep 2022 11:34:08 +0000 (+0200) Subject: spi: Ensure that sg_table won't be used after being freed X-Git-Tag: v5.19.17~435 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=37ad7c5990c038060cca8e6a87a93399f5a6dfc2;p=thirdparty%2Fkernel%2Fstable.git 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 Link: https://lore.kernel.org/r/20220930113408.19720-1-m.szyprowski@samsung.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 2c616024f7c02..f595e516058c2 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1047,6 +1047,8 @@ 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; } }