The patch below does not apply to the 4.20-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a55234dabe1f72cf22f9197980751d37e38ba020 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= u.kleine-koenig@pengutronix.de Date: Fri, 11 Jan 2019 12:20:41 +0100 Subject: [PATCH] can: flexcan: fix NULL pointer exception during bringup MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
Commit cbffaf7aa09e ("can: flexcan: Always use last mailbox for TX") introduced a loop letting i run up to (including) ARRAY_SIZE(regs->mb) and in the body accessed regs->mb[i] which is an out-of-bounds array access that then resulted in an access to an reserved register area.
Later this was changed by commit 0517961ccdf1 ("can: flexcan: Add provision for variable payload size") to iterate a bit differently but still runs one iteration too much resulting to call
flexcan_get_mb(priv, priv->mb_count)
which results in a WARN_ON and then a NULL pointer exception. This only affects devices compatible with "fsl,p1010-flexcan", "fsl,imx53-flexcan", "fsl,imx35-flexcan", "fsl,imx25-flexcan", "fsl,imx28-flexcan", so newer i.MX SoCs are not affected.
Fixes: cbffaf7aa09e ("can: flexcan: Always use last mailbox for TX") Signed-off-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Cc: linux-stable stable@vger.kernel.org # >= 4.20 Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de
diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 5f097648d12d..1c66fb2ad76b 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -1106,7 +1106,7 @@ static int flexcan_chip_start(struct net_device *dev) } } else { /* clear and invalidate unused mailboxes first */ - for (i = FLEXCAN_TX_MB_RESERVED_OFF_FIFO; i <= priv->mb_count; i++) { + for (i = FLEXCAN_TX_MB_RESERVED_OFF_FIFO; i < priv->mb_count; i++) { mb = flexcan_get_mb(priv, i); priv->write(FLEXCAN_MB_CODE_RX_INACTIVE, &mb->can_ctrl);