mtd: rawnand: atmel: Fix potential NULL pointer dereference

BugLink: https://bugs.launchpad.net/bugs/1836802
[ Upstream commit fbed20280d912449cfb40c382cb55e3d11502587 ]

There is a potential execution path in which function
of_find_compatible_node() returns NULL. In such a case,
we end up having a NULL pointer dereference when accessing
pointer *nfc_np* in function of_clk_get().

So, we better don't take any chances and fix this by null
checking pointer *nfc_np* before calling of_clk_get().

Addresses-Coverity-ID: 1473052 ("Dereference null return value")
Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Acked-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/mtd/nand/atmel/nand-controller.c b/drivers/mtd/nand/atmel/nand-controller.c
index 38adc320aa763b32a1e758d75d6f30862426ca1c..1d9a096fca655693143f67626139b79607bfae85 100644 (file)
--- a/drivers/mtd/nand/atmel/nand-controller.c
+++ b/drivers/mtd/nand/atmel/nand-controller.c
@@ -2078,6 +2078,10 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
        nand_np = dev->of_node;
        nfc_np = of_find_compatible_node(dev->of_node, NULL,
                                         "atmel,sama5d3-nfc");
+       if (!nfc_np) {
+               dev_err(dev, "Could not find device node for sama5d3-nfc\n");
+               return -ENODEV;
+       }
 
        nc->clk = of_clk_get(nfc_np, 0);
        if (IS_ERR(nc->clk)) {