Commit 76668d2a authored Jul 19, 2022 by Marc Kleine-Budde Committed by Greg Kroah-Hartman Jul 29, 2022

spi: bcm2835: bcm2835_spi_handle_err(): fix NULL pointer deref for non DMA transfers



commit 4ceaa684459d414992acbefb4e4c31f2dfc50641 upstream.

In case a IRQ based transfer times out the bcm2835_spi_handle_err()
function is called. Since commit 1513ceee ("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: 1513ceee ("spi: bcm2835: Drop dma_pending flag")
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/r/20220719072234.2782764-1-mkl@pengutronix.de


Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 50a1d3d0

drivers/spi/spi-bcm2835.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -1159,10 +1159,14 @@ 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 */
		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 */