Patch "phylib: fix device deletion order in mdiobus_unregister()" has been added to the 4.2-stable tree
Subsystems (3)
This is a note to let you know that I've just added the patch titled
phylib: fix device deletion order in mdiobus_unregister()
to the 4.2-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:
phylib-fix-device-deletion-order-in-mdiobus_unregister.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From foo@baz Wed Sep 30 05:25:07 CEST 2015
From: Mark Salter <[email protected]>
Date: Tue, 1 Sep 2015 09:36:05 -0400
Subject: phylib: fix device deletion order in mdiobus_unregister()
From: Mark Salter <[email protected]>
[ Upstream commit b6c6aedcbcbacd7b0cb4b64ed5ac835bc1c60a03 ]
commit 8b63ec1837fa ("phylib: Make PHYs children of their MDIO bus, not the bus' parent.") uncovered a problem in mdiobus_unregister() which leads to this warning when I reboot an APM Mustang (arm64) platform:
WARNING: CPU: 7 PID: 4239 at fs/sysfs/group.c:224 sysfs_remove_group+0xa0/0xa4() sysfs group fffffe0000e07a10 not found for kobject 'xgene-mii-eth0:03' ... CPU: 7 PID: 4239 Comm: reboot Tainted: G E 4.2.0-0.18.el7.test15.aarch64 #1 Hardware name: AppliedMicro Mustang/Mustang, BIOS 1.1.0 Aug 26 2015 Call Trace: [<fffffe000009739c>] dump_backtrace+0x0/0x170 [<fffffe000009752c>] show_stack+0x20/0x2c [<fffffe00007436f0>] dump_stack+0x78/0x9c [<fffffe00000c2cb4>] warn_slowpath_common+0xa0/0xd8 [<fffffe00000c2d60>] warn_slowpath_fmt+0x74/0x88 [<fffffe0000293d3c>] sysfs_remove_group+0x9c/0xa4 [<fffffe00004a8bac>] dpm_sysfs_remove+0x5c/0x70 [<fffffe000049b388>] device_del+0x44/0x208 [<fffffe000049b578>] device_unregister+0x2c/0x7c [<fffffe000050dc68>] mdiobus_unregister+0x48/0x94 [<fffffe000052afd0>] xgene_enet_mdio_remove+0x28/0x44 [<fffffe000052d3f0>] xgene_enet_remove+0xd0/0xd8 [<fffffe000052d424>] xgene_enet_shutdown+0x2c/0x3c [<fffffe00004a204c>] platform_drv_shutdown+0x24/0x40 [<fffffe000049d4f4>] device_shutdown+0xf0/0x1b4 [<fffffe00000e31ec>] kernel_restart_prepare+0x40/0x4c [<fffffe00000e32f8>] kernel_restart+0x1c/0x80 [<fffffe00000e3670>] SyS_reboot+0x17c/0x250
The problem is that mdiobus_unregister() deletes the bus device before unregistering the phy devices on the bus. This wasn't a problem before because the phys were not children of the bus:
/sys/devices/platform/APMC0D05:00/net/eth0/xgene-mii-eth0:03 /sys/devices/platform/APMC0D05:00/net/eth0/xgene-mii-eth0
But now that they are:
/sys/devices/platform/APMC0D05:00/net/eth0/xgene-mii-eth0/xgene-mii-eth0:03
when mdiobus_unregister deletes the bus device, the phy subdirs are removed from sysfs also. So when the phys are unregistered afterward, we get the warning. This patch changes the order so that phys are unregistered before the bus device is deleted.
--- drivers/net/phy/mdio_bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/net/phy/mdio_bus.c +1 -1
@@ -303,12 +303,12 @@ void mdiobus_unregister(struct mii_bus *BUG_ON (bus->state !=MDIOBUS_REGISTERED ); bus->state =MDIOBUS_UNREGISTERED ; -device_del (&bus->dev);for (i =0 ; i <PHY_MAX_ADDR ; i++) {if (bus->phy_map[i])device_unregister (&bus->phy_map[i]->dev); bus->phy_map[i] =NULL ; } +device_del (&bus->dev); }EXPORT_SYMBOL (mdiobus_unregister);
Patches currently in stable-queue which might be from [email protected] are
queue-4.2/phylib-fix-device-deletion-order-in-mdiobus_unregister.patch