* [PATCH v2] spi: bcm2835: bcm2835_spi_handle_err(): fix NULL pointer deref for non DMA transfers
@ 2022-07-20 13:34 Marc Kleine-Budde
0 siblings, 0 replies; only message in thread
From: Marc Kleine-Budde @ 2022-07-20 13:34 UTC (permalink / raw)
To: linux-spi
Cc: kernel, Marc Kleine-Budde, Lukas Wunner, Mark Brown, Jens Lindahl
In case a IRQ based transfer times out the bcm2835_spi_handle_err()
function is called. Since commit 1513ceee70f2 ("spi: bcm2835: Drop
dma_pending flag") the TX and RX DMA transfers are unconditionally
canceled, leading to NULL pointer derefs if ctlr->dma_tx or
ctlr->dma_rx are not set.
Fix the NULL pointer deref by checking that ctlr->dma_tx and
ctlr->dma_rx are valid pointers before accessing them.
Fixes: 1513ceee70f2 ("spi: bcm2835: Drop dma_pending flag")
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jens Lindahl <jensctl@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
Changes Since v1: https://lore.kernel.org/all/20220719072234.2782764-1-mkl@pengutronix.de
- added Mark Brown and Jens Lindahl on Cc
drivers/spi/spi-bcm2835.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index 775c0bf2f923..0933948d7df3 100644
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -1138,10 +1138,14 @@ static void bcm2835_spi_handle_err(struct spi_controller *ctlr,
struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr);
/* if an error occurred and we have an active dma, then terminate */
- dmaengine_terminate_sync(ctlr->dma_tx);
- bs->tx_dma_active = false;
- dmaengine_terminate_sync(ctlr->dma_rx);
- bs->rx_dma_active = false;
+ if (ctlr->dma_tx) {
+ dmaengine_terminate_sync(ctlr->dma_tx);
+ bs->tx_dma_active = false;
+ }
+ if (ctlr->dma_rx) {
+ dmaengine_terminate_sync(ctlr->dma_rx);
+ bs->rx_dma_active = false;
+ }
bcm2835_spi_undo_prologue(bs);
/* and reset */
base-commit: 73d5fe046270281a46344e06bf986c607632f7ea
--
2.35.1
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