Patch "ARM: orion: fix orion_ge00_switch_board_info initialization" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

ARM: orion: fix orion_ge00_switch_board_info initialization

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm-orion-fix-orion_ge00_switch_board_info-initialization.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Arnd Bergmann <[email protected]>
Date: Wed, 21 Feb 2018 13:18:49 +0100
Subject: ARM: orion: fix orion_ge00_switch_board_info initialization

From: Arnd Bergmann <[email protected]>

commit 8337d083507b9827dfb36d545538b7789df834fd upstream.

A section type mismatch warning shows up when building with LTO, since orion_ge00_mvmdio_bus_name was put in __initconst but not marked const itself:

include/linux/of.h: In function 'spear_setup_of_timer':
arch/arm/mach-spear/time.c:207:34: error: 'timer_of_match' causes a section type conflict with 'orion_ge00_mvmdio_bus_name'

 static const struct of_device_id timer_of_match[] __initconst = {
                                  ^
arch/arm/plat-orion/common.c:475:32: note: 'orion_ge00_mvmdio_bus_name' was declared here
 static __initconst const char *orion_ge00_mvmdio_bus_name = "orion-mii";
                                ^

As pointed out by Andrew Lunn, it should in fact be 'const' but not '__initconst' because the string is never copied but may be accessed after the init sections are freed. To fix that, I get rid of the extra symbol and rewrite the initialization in a simpler way that assigns both the bus_id and modalias statically.

I spotted another theoretical bug in the same place, where d->netdev[i] may be an out of bounds access, this can be fixed by moving the device assignment into the loop.

---
 arch/arm/plat-orion/common.c |   23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

@@ -472,28 +472,27 @@ void __init orion_ge11_init(struct mv643
 /*****************************************************************************
  * Ethernet switch
  ****************************************************************************/
-static __initconst const char *orion_ge00_mvmdio_bus_name = "orion-mii";
-static __initdata struct mdio_board_info
-		  orion_ge00_switch_board_info;
+static __initdata struct mdio_board_info orion_ge00_switch_board_info = {
+	.bus_id   = "orion-mii",
+	.modalias = "mv88e6085",
+};
 
 void __init orion_ge00_switch_init(struct dsa_chip_data *d)
 {
-	struct mdio_board_info *bd;
 	unsigned int i;
 
 	if (!IS_BUILTIN(CONFIG_PHYLIB))
 		return;
 
-	for (i = 0; i < ARRAY_SIZE(d->port_names); i++)
-		if (!strcmp(d->port_names[i], "cpu"))
+	for (i = 0; i < ARRAY_SIZE(d->port_names); i++) {
+		if (!strcmp(d->port_names[i], "cpu")) {
+			d->netdev[i] = &orion_ge00.dev;
 			break;
+		}
+	}
 
-	bd = &orion_ge00_switch_board_info;
-	bd->bus_id = orion_ge00_mvmdio_bus_name;
-	bd->mdio_addr = d->sw_addr;
-	d->netdev[i] = &orion_ge00.dev;
-	strcpy(bd->modalias, "mv88e6085");
-	bd->platform_data = d;
+	orion_ge00_switch_board_info.mdio_addr = d->sw_addr;
+	orion_ge00_switch_board_info.platform_data = d;
 
 	mdiobus_register_board_info(&orion_ge00_switch_board_info, 1);
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/ipv6-sit-work-around-bogus-gcc-8-wrestrict-warning.patch queue-4.15/arm-kvm-fix-building-with-gcc-8.patch queue-4.15/arm-orion-fix-orion_ge00_switch_board_info-initialization.patch