ARM: imx: Fix boot crash if ocotp is not found

cdleonard · zandrey · commit ca4bdbaeb69a · 2020-05-30T20:14:46.000Z
The imx_soc_device_init functions tries to fetch the ocotp regmap in order to soc serial number. If regmap fetch fails then a message is printed but regmap_read is called anyway and the system crashes. Failing to lookup ocotp regmap shouldn't be a fatal boot error so check that the pointer is valid. Only side-effect of ocotp lookup failure now is that serial number will be reported as all-zeros which is acceptable. Cc: stable@vger.kernel.org Fixes: 8267ff8 ("ARM: imx: Add serial number support for i.MX6/7 SoCs") Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Tested-by: Christoph Niedermaier <cniedermaier@dh-electronics.com> Signed-off-by: Shawn Guo <shawnguo@kernel.org> (cherry picked from commit 7947e32)
diff --git a/arch/arm/mach-imx/cpu.c b/arch/arm/mach-imx/cpu.c
@@ -84,7 +84,7 @@ struct device * __init imx_soc_device_init(void)
 	const char *ocotp_compat = NULL;
 	struct soc_device *soc_dev;
 	struct device_node *root;
-	struct regmap *ocotp;
+	struct regmap *ocotp = NULL;
 	const char *soc_id;
 	u64 soc_uid = 0;
 	u32 val;
@@ -178,7 +178,9 @@ struct device * __init imx_soc_device_init(void)
 		ocotp = syscon_regmap_lookup_by_compatible(ocotp_compat);
 		if (IS_ERR(ocotp))
 			pr_err("%s: failed to find %s regmap!\n", __func__, ocotp_compat);
+	}
 
+	if (!IS_ERR_OR_NULL(ocotp)) {
 		regmap_read(ocotp, OCOTP_UID_H, &val);
 		soc_uid = val;
 		regmap_read(ocotp, OCOTP_UID_L, &val);
