Commits
Craig Gallek committed 86dfb4acb37
tun: Don't assume type tun in tun_device_event
The referenced change added a netlink notifier for processing
device queue size events. These events are fired for all devices
but the registered callback assumed they only occurred for tun
devices. This fix adds a check (borrowed from macvtap.c) to discard
non-tun device events.
For reference, this fixes the following splat:
[ 71.505935] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
[ 71.513870] IP: [<ffffffff8153c1a0>] tun_device_event+0x110/0x340
[ 71.519906] PGD 3f41f56067 PUD 3f264b7067 PMD 0
[ 71.524497] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
[ 71.529374] gsmi: Log Shutdown Reason 0x03
[ 71.533417] Modules linked in:[ 71.533826] mlx4_en: eth1: Link Up
[ 71.539616] bonding w1_therm wire cdc_acm ehci_pci ehci_hcd mlx4_en ib_uverbs mlx4_ib ib_core mlx4_core
[ 71.549282] CPU: 12 PID: 7915 Comm: set.ixion-haswe Not tainted 4.7.0-dbx-DEV #8
[ 71.556586] Hardware name: Intel Grantley,Wellsburg/Ixion_IT_15, BIOS 2.58.0 05/03/2016
[ 71.564495] task: ffff887f00bb20c0 ti: ffff887f00798000 task.ti: ffff887f00798000
[ 71.571894] RIP: 0010:[<ffffffff8153c1a0>] [<ffffffff8153c1a0>] tun_device_event+0x110/0x340
[ 71.580327] RSP: 0018:ffff887f0079bbd8 EFLAGS: 00010202
[ 71.585576] RAX: fffffffffffffae8 RBX: ffff887ef6d03378 RCX: 0000000000000000
[ 71.592624] RDX: 0000000000000000 RSI: 0000000000000028 RDI: 0000000000000000
[ 71.599675] RBP: ffff887f0079bc48 R08: 0000000000000000 R09: 0000000000000001
[ 71.606730] R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000010
[ 71.613780] R13: 0000000000000000 R14: 0000000000000001 R15: ffff887f0079bd00
[ 71.620832] FS: 00007f5cdc581700(0000) GS:ffff883f7f700000(0000) knlGS:0000000000000000
[ 71.628826] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 71.634500] CR2: 0000000000000010 CR3: 0000003f3eb62000 CR4: 00000000001406e0
[ 71.641549] Stack:
[ 71.643533] ffff887f0079bc08 0000000000000246 000000000000001e ffff887ef6d00000
[ 71.650871] ffff887f0079bd00 0000000000000000 0000000000000000 ffffffff00000000
[ 71.658210] ffff887f0079bc48 ffffffff81d24070 00000000fffffff9 ffffffff81cec7a0
[ 71.665549] Call Trace:
[ 71.667975] [<ffffffff810eeb0d>] notifier_call_chain+0x5d/0x80
[ 71.673823] [<ffffffff816365d0>] ? show_tx_maxrate+0x30/0x30
[ 71.679502] [<ffffffff810eeb3e>] __raw_notifier_call_chain+0xe/0x10
[ 71.685778] [<ffffffff810eeb56>] raw_notifier_call_chain+0x16/0x20
[ 71.691976] [<ffffffff8160eb30>] call_netdevice_notifiers_info+0x40/0x70
[ 71.698681] [<ffffffff8160ec36>] call_netdevice_notifiers+0x16/0x20
[ 71.704956] [<ffffffff81636636>] change_tx_queue_len+0x66/0x90
[ 71.710807] [<ffffffff816381ef>] netdev_store.isra.5+0xbf/0xd0
[ 71.716658] [<ffffffff81638350>] tx_queue_len_store+0x50/0x60
[ 71.722431] [<ffffffff814a6798>] dev_attr_store+0x18/0x30
[ 71.727857] [<ffffffff812ea3ff>] sysfs_kf_write+0x4f/0x70
[ 71.733274] [<ffffffff812e9507>] kernfs_fop_write+0x147/0x1d0
[ 71.739045] [<ffffffff81134a4f>] ? rcu_read_lock_sched_held+0x8f/0xa0
[ 71.745499] [<ffffffff8125a108>] __vfs_write+0x28/0x120
[ 71.750748] [<ffffffff8111b137>] ? percpu_down_read+0x57/0x90
[ 71.756516] [<ffffffff8125d7d8>] ? __sb_start_write+0xc8/0xe0
[ 71.762278] [<ffffffff8125d7d8>] ? __sb_start_write+0xc8/0xe0
[ 71.768038] [<ffffffff8125bd5e>] vfs_write+0xbe/0x1b0
[ 71.773113] [<ffffffff8125c092>] SyS_write+0x52/0xa0
[ 71.778110] [<ffffffff817528e5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 71.784472] Code: 45 31 f6 48 8b 93 78 33 00 00 48 81 c3 78 33 00 00 48 39 d3 48 8d 82 e8 fa ff ff 74 25 48 8d b0 40 05 00 00 49 63 d6 41 83 c6 01 <49> 89 34 d4 48 8b 90 18 05 00 00 48 39 d3 48 8d 82 e8 fa ff ff
[ 71.803655] RIP [<ffffffff8153c1a0>] tun_device_event+0x110/0x340
[ 71.809769] RSP <ffff887f0079bbd8>
[ 71.813213] CR2: 0000000000000010
[ 71.816512] ---[ end trace 4db6449606319f73 ]---
Fixes: 1576d9860599 ("tun: switch to use skb array for tx")
Signed-off-by: Craig Gallek <kraig@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>