spi: Ensure that sg_table won't be used after being freed

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: 0c17ba7 ("spi: Fix cache corruption due to DMA/PIO overlap") Signed-off-by: Marek Szyprowski <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Mark Brown <[email protected]>
shankerd04 · Sep 30, 2022 · 8e9204c · 8e9204c
1 parent 28366dd
commit 8e9204c
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
@@ -1102,6 +1102,8 @@ static void spi_unmap_buf_attrs(struct spi_controller *ctlr,
 	if (sgt->orig_nents) {
 		dma_unmap_sgtable(dev, sgt, dir, attrs);
 		sg_free_table(sgt);
+		sgt->orig_nents = 0;
+		sgt->nents = 0;
 	}
 }