Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.2 01/30] phylib: fix device deletion order in mdiobus_unregister() | Date | Thu, 1 Oct 2015 11:21:23 +0200 |
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4.2-stable review patch. If anyone has any objections, please let me know.
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From: Mark Salter <msalter@redhat.com>
[ 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.
Fixes: 8b63ec1837fa ("phylib: Make PHYs children of their MDIO bus, not the bus' parent.") Signed-off-by: Mark Salter <msalter@redhat.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Tested-by: Mark Langsdorf <mlangsdo@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/net/phy/mdio_bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -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);
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