RE: [net-next 08/13] fsl/fman: check pcsphy pointer before use

-----Original Message-----
From: David Laight [mailto:David.Laight@ACULAB.COM]
Sent: Tuesday, October 04, 2016 5:44 PM
To: Madalin-Cristian Bucur <madalin.bucur@nxp.com>;
netdev@vger.kernel.org
Cc: linuxdev.baldrick@gmail.com; linuxppc-dev@lists.ozlabs.org;
davem@davemloft.net; linux-kernel@vger.kernel.org
Subject: RE: [net-next 08/13] fsl/fman: check pcsphy pointer before use

From: Madalin Bucur

quoted

Sent: 04 October 2016 08:33
Subject: [net-next 08/13] fsl/fman: check pcsphy pointer before use

..

quoted

--- a/drivers/net/ethernet/freescale/fman/fman_memac.c
+++ b/drivers/net/ethernet/freescale/fman/fman_memac.c

@@ -507,6 +507,9 @@ static void setup_sgmii_internal_phy(struct

fman_mac *memac,

quoted

 {
 	u16 tmp_reg16;

+	if (WARN_ON(!memac->pcsphy))
+		return;
+

Why?

Either it can validly be NULL in which case you don't want the message.
Or it shouldn't be NULL in which case you need to find and fix the bug.
The later kernel OOPS will make the bug much easier to find.

	David

You can get into that situation if you have a broken device tree, state into
which someone may get while trying to create the device tree for a new
board. Avoiding a crash here allows the user to look at the device trees as
seen by the kernel / add some debug code if needed.

Madalin