4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alexander Graf agraf@suse.de
[ Upstream commit 92571a1aae40d291158d16e7142637908220f470 ]
When using wicked with a lan78xx device attached to the system, we end up with ethtool commands issued on the device before an ifup got issued. That lead to the following crash:
Unable to handle kernel NULL pointer dereference at virtual address 0000039c pgd = ffff800035b30000 [0000039c] *pgd=0000000000000000 Internal error: Oops: 96000004 [#1] SMP Modules linked in: [...] Supported: Yes CPU: 3 PID: 638 Comm: wickedd Tainted: G E 4.12.14-0-default #1 Hardware name: raspberrypi rpi/rpi, BIOS 2018.03-rc2 02/21/2018 task: ffff800035e74180 task.stack: ffff800036718000 PC is at phy_ethtool_ksettings_get+0x20/0x98 LR is at lan78xx_get_link_ksettings+0x44/0x60 [lan78xx] pc : [<ffff0000086f7f30>] lr : [<ffff000000dcca84>] pstate: 20000005 sp : ffff80003671bb20 x29: ffff80003671bb20 x28: ffff800035e74180 x27: ffff000008912000 x26: 000000000000001d x25: 0000000000000124 x24: ffff000008f74d00 x23: 0000004000114809 x22: 0000000000000000 x21: ffff80003671bbd0 x20: 0000000000000000 x19: ffff80003671bbd0 x18: 000000000000040d x17: 0000000000000001 x16: 0000000000000000 x15: 0000000000000000 x14: ffffffffffffffff x13: 0000000000000000 x12: 0000000000000020 x11: 0101010101010101 x10: fefefefefefefeff x9 : 7f7f7f7f7f7f7f7f x8 : fefefeff31677364 x7 : 0000000080808080 x6 : ffff80003671bc9c x5 : ffff80003671b9f8 x4 : ffff80002c296190 x3 : 0000000000000000 x2 : 0000000000000000 x1 : ffff80003671bbd0 x0 : ffff80003671bc00 Process wickedd (pid: 638, stack limit = 0xffff800036718000) Call trace: Exception stack(0xffff80003671b9e0 to 0xffff80003671bb20) b9e0: ffff80003671bc00 ffff80003671bbd0 0000000000000000 0000000000000000 ba00: ffff80002c296190 ffff80003671b9f8 ffff80003671bc9c 0000000080808080 ba20: fefefeff31677364 7f7f7f7f7f7f7f7f fefefefefefefeff 0101010101010101 ba40: 0000000000000020 0000000000000000 ffffffffffffffff 0000000000000000 ba60: 0000000000000000 0000000000000001 000000000000040d ffff80003671bbd0 ba80: 0000000000000000 ffff80003671bbd0 0000000000000000 0000004000114809 baa0: ffff000008f74d00 0000000000000124 000000000000001d ffff000008912000 bac0: ffff800035e74180 ffff80003671bb20 ffff000000dcca84 ffff80003671bb20 bae0: ffff0000086f7f30 0000000020000005 ffff80002c296000 ffff800035223900 bb00: 0000ffffffffffff 0000000000000000 ffff80003671bb20 ffff0000086f7f30 [<ffff0000086f7f30>] phy_ethtool_ksettings_get+0x20/0x98 [<ffff000000dcca84>] lan78xx_get_link_ksettings+0x44/0x60 [lan78xx] [<ffff0000087cbc40>] ethtool_get_settings+0x68/0x210 [<ffff0000087cc0d4>] dev_ethtool+0x214/0x2180 [<ffff0000087e5008>] dev_ioctl+0x400/0x630 [<ffff00000879dd00>] sock_do_ioctl+0x70/0x88 [<ffff00000879f5f8>] sock_ioctl+0x208/0x368 [<ffff0000082cde10>] do_vfs_ioctl+0xb0/0x848 [<ffff0000082ce634>] SyS_ioctl+0x8c/0xa8 Exception stack(0xffff80003671bec0 to 0xffff80003671c000) bec0: 0000000000000009 0000000000008946 0000fffff4e841d0 0000aa0032687465 bee0: 0000aaaafa2319d4 0000fffff4e841d4 0000000032687465 0000000032687465 bf00: 000000000000001d 7f7fff7f7f7f7f7f 72606b622e71ff4c 7f7f7f7f7f7f7f7f bf20: 0101010101010101 0000000000000020 ffffffffffffffff 0000ffff7f510c68 bf40: 0000ffff7f6a9d18 0000ffff7f44ce30 000000000000040d 0000ffff7f6f98f0 bf60: 0000fffff4e842c0 0000000000000001 0000aaaafa2c2e00 0000ffff7f6ab000 bf80: 0000fffff4e842c0 0000ffff7f62a000 0000aaaafa2b9f20 0000aaaafa2c2e00 bfa0: 0000fffff4e84818 0000fffff4e841a0 0000ffff7f5ad0cc 0000fffff4e841a0 bfc0: 0000ffff7f44ce3c 0000000080000000 0000000000000009 000000000000001d bfe0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
The culprit is quite simple: The driver tries to access the phy left and right, but only actually has a working reference to it when the device is up.
The fix thus is quite simple too: Get a reference to the phy on probe already and keep it even when the device is going down.
With this patch applied, I can successfully run wicked on my system and bring the interface up and down as many times as I want, without getting NULL pointer dereferences in between.
Signed-off-by: Alexander Graf agraf@suse.de Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/usb/lan78xx.c | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-)
--- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -2083,10 +2083,6 @@ static int lan78xx_phy_init(struct lan78
dev->fc_autoneg = phydev->autoneg;
- phy_start(phydev); - - netif_dbg(dev, ifup, dev->net, "phy initialised successfully"); - return 0;
error: @@ -2523,9 +2519,9 @@ static int lan78xx_open(struct net_devic if (ret < 0) goto done;
- ret = lan78xx_phy_init(dev); - if (ret < 0) - goto done; + phy_start(net->phydev); + + netif_dbg(dev, ifup, dev->net, "phy initialised successfully");
/* for Link Check */ if (dev->urb_intr) { @@ -2586,13 +2582,8 @@ static int lan78xx_stop(struct net_devic if (timer_pending(&dev->stat_monitor)) del_timer_sync(&dev->stat_monitor);
- phy_unregister_fixup_for_uid(PHY_KSZ9031RNX, 0xfffffff0); - phy_unregister_fixup_for_uid(PHY_LAN8835, 0xfffffff0); - - phy_stop(net->phydev); - phy_disconnect(net->phydev); - - net->phydev = NULL; + if (net->phydev) + phy_stop(net->phydev);
clear_bit(EVENT_DEV_OPEN, &dev->flags); netif_stop_queue(net); @@ -3507,8 +3498,13 @@ static void lan78xx_disconnect(struct us return;
udev = interface_to_usbdev(intf); - net = dev->net; + + phy_unregister_fixup_for_uid(PHY_KSZ9031RNX, 0xfffffff0); + phy_unregister_fixup_for_uid(PHY_LAN8835, 0xfffffff0); + + phy_disconnect(net->phydev); + unregister_netdev(net);
cancel_delayed_work_sync(&dev->wq); @@ -3668,8 +3664,14 @@ static int lan78xx_probe(struct usb_inte pm_runtime_set_autosuspend_delay(&udev->dev, DEFAULT_AUTOSUSPEND_DELAY);
+ ret = lan78xx_phy_init(dev); + if (ret < 0) + goto out4; + return 0;
+out4: + unregister_netdev(netdev); out3: lan78xx_unbind(dev, intf); out2: @@ -4017,7 +4019,7 @@ static int lan78xx_reset_resume(struct u
lan78xx_reset(dev);
- lan78xx_phy_init(dev); + phy_start(dev->net->phydev);
return lan78xx_resume(intf); }