general protection fault in hsr_dev_change_mtu

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 9fa690a2 Linux 4.14.169
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=153ee101e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=eb55b601e76e3476
dashboard link: https://syzkaller.appspot.com/bug?extid=3aa4e524b682ef6a2728
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3aa4e5...@syzkaller.appspotmail.com

netlink: 20 bytes leftover after parsing attributes in process `syz-executor.2'.
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 10007 Comm: syz-executor.2 Not tainted 4.14.169-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888076c6e240 task.stack: ffff88808a330000
RIP: 0010:hsr_dev_change_mtu+0x9f/0xd0 net/hsr/hsr_device.c:149
RSP: 0018:ffff88808a336fd0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888057072d40 RCX: ffffc90013b59000
RDX: 0000000000000002 RSI: ffffffff866093ca RDI: 0000000000000010
RBP: ffff88808a336ff0 R08: ffff888076c6e240 R09: 0000000000000002
R10: 0000000000000000 R11: ffff888076c6e240 R12: 00000000000005dc
R13: ffff888057073800 R14: 0000000000000000 R15: ffff88808a337080
FS: 00007fc2196d0700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000625208 CR3: 000000008c439000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__dev_set_mtu net/core/dev.c:6877 [inline]
dev_set_mtu+0x1f0/0x400 net/core/dev.c:6912
team_port_add drivers/net/team/team.c:1195 [inline]
team_add_slave+0x851/0x1860 drivers/net/team/team.c:1964
do_set_master net/core/rtnetlink.c:1961 [inline]
do_set_master+0x19f/0x200 net/core/rtnetlink.c:1936
do_setlink+0x99f/0x2c20 net/core/rtnetlink.c:2098
rtnl_newlink+0x11a7/0x1700 net/core/rtnetlink.c:2660
rtnetlink_rcv_msg+0x3da/0xb70 net/core/rtnetlink.c:4315
netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:4327
netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
netlink_unicast+0x44d/0x650 net/netlink/af_netlink.c:1312
netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xce/0x110 net/socket.c:656
___sys_sendmsg+0x70a/0x840 net/socket.c:2062
__sys_sendmsg+0xb9/0x140 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x2d/0x50 net/socket.c:2103
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45b349
RSP: 002b:00007fc2196cfc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc2196d06d4 RCX: 000000000045b349
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009c7 R14: 00000000004cb327 R15: 000000000075bf2c
Code: e0 5b 41 5c 41 5d 41 5e 5d c3 e8 fd 11 27 fb eb de e8 d6 80 fc fa 49 8d 7e 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 1d 49 8b 7e 10 ba 06 00 00 00 48 c7 c6 60 8a 70
RIP: hsr_dev_change_mtu+0x9f/0xd0 net/hsr/hsr_device.c:149 RSP: ffff88808a336fd0
---[ end trace 6dd7fd6fc50b518f ]---


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.