From: Uwe Kleine-König Date: Fri, 11 Jan 2019 11:20:41 +0000 (+0100) Subject: can: flexcan: fix NULL pointer exception during bringup X-Git-Tag: rel_imx_4.19.35_1.1.0~6972 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=6f4f2a443d87e964ebdbb2543cbd7df285cd6080;p=linux.git can: flexcan: fix NULL pointer exception during bringup commit a55234dabe1f72cf22f9197980751d37e38ba020 upstream. 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 Cc: linux-stable # >= 4.20 Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 75ce11395ee8..ae219b8a7754 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -1004,7 +1004,7 @@ 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 <= ARRAY_SIZE(regs->mb); i++) { + for (i = FLEXCAN_TX_MB_RESERVED_OFF_FIFO; i < ARRAY_SIZE(regs->mb); i++) { priv->write(FLEXCAN_MB_CODE_RX_INACTIVE, ®s->mb[i].can_ctrl); }