general protection fault in dst_dev_put

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a8ad60f2af58 Linux 4.14.305
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1294003f480000
kernel config: https://syzkaller.appspot.com/x/.config?x=2f23dc9802022031
dashboard link: https://syzkaller.appspot.com/bug?extid=358610448d686544e7b8
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c38348fd389d/disk-a8ad60f2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3a775d221689/vmlinux-a8ad60f2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/32e71e04d2b4/bzImage-a8ad60f2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+358610...@syzkaller.appspotmail.com

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: 11050 Comm: syz-executor.0 Not tainted 4.14.305-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
task: ffff88808f628500 task.stack: ffff888097b88000
RIP: 0010:dst_dev_put+0x1f/0x2b0 net/core/dst.c:165
RSP: 0018:ffff888097b8ea68 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc900090e6000
RDX: 0000000000000000 RSI: ffffffff85c6702e RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffff89d1e140 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000007
R13: ffff88809f4e61c0 R14: fffffbfff141291e R15: 0000000000000001
FS: 00007f8510b0c700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005565e727f080 CR3: 000000009b78e000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rt6_free_pcpu.part.0+0xed/0x1f0 net/ipv6/ip6_fib.c:183
rt6_free_pcpu net/ipv6/ip6_fib.c:173 [inline]
rt6_release include/net/ip6_fib.h:229 [inline]
fib6_del_route net/ipv6/ip6_fib.c:1586 [inline]
fib6_del+0x9d6/0xda0 net/ipv6/ip6_fib.c:1626
fib6_clean_node+0x258/0x470 net/ipv6/ip6_fib.c:1778
fib6_walk_continue+0x1e5/0x700 net/ipv6/ip6_fib.c:1704
fib6_walk+0x177/0x350 net/ipv6/ip6_fib.c:1749
fib6_clean_tree+0xc1/0xf0 net/ipv6/ip6_fib.c:1823
__fib6_clean_all+0xfd/0x230 net/ipv6/ip6_fib.c:1839
rt6_ifdown+0x7d/0x5b0 net/ipv6/route.c:2906
addrconf_ifdown.isra.0+0xb9/0x1410 net/ipv6/addrconf.c:3588
addrconf_notify+0x116/0x1c50 net/ipv6/addrconf.c:3511
notifier_call_chain+0x108/0x1a0 kernel/notifier.c:93
call_netdevice_notifiers_info net/core/dev.c:1667 [inline]
call_netdevice_notifiers net/core/dev.c:1683 [inline]
__dev_notify_flags+0x187/0x260 net/core/dev.c:6842
dev_change_flags+0xe6/0x130 net/core/dev.c:6873
do_setlink+0x83f/0x2bf0 net/core/rtnetlink.c:2092
rtnl_group_changelink net/core/rtnetlink.c:2512 [inline]
rtnl_newlink+0xc9d/0x1830 net/core/rtnetlink.c:2668
rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4322
netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2461
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x651/0xbc0 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xb5/0x100 net/socket.c:656
___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
__sys_sendmsg+0xa3/0x120 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x27/0x40 net/socket.c:2103
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x5e/0xd3
RIP: 0033:0x7f85125fd0f9
RSP: 002b:00007f8510b0c168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f851271d1f0 RCX: 00007f85125fd0f9
RDX: 0000000000000000 RSI: 0000000020006440 RDI: 000000000000000a
RBP: 00007f8512658ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcbcba7b4f R14: 00007f8510b0c300 R15: 0000000000022000
Code: c3 66 66 2e 0f 1f 84 00 00 00 00 00 41 55 41 54 55 53 48 89 fb e8 82 e6 8e fb 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 0a 02 00 00 48 8d 7b 64 48 8b 2b 48 b8 00 00
RIP: dst_dev_put+0x1f/0x2b0 net/core/dst.c:165 RSP: ffff888097b8ea68
---[ end trace 95abd2c1965f7480 ]---
----------------
Code disassembly (best guess):
0: c3 retq
1: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1)
8: 00 00 00 00
c: 41 55 push %r13
e: 41 54 push %r12
10: 55 push %rbp
11: 53 push %rbx
12: 48 89 fb mov %rdi,%rbx
15: e8 82 e6 8e fb callq 0xfb8ee69c
1a: 48 89 da mov %rbx,%rdx
1d: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
24: fc ff df
27: 48 c1 ea 03 shr $0x3,%rdx
* 2b: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2f: 0f 85 0a 02 00 00 jne 0x23f
35: 48 8d 7b 64 lea 0x64(%rbx),%rdi
39: 48 8b 2b mov (%rbx),%rbp
3c: 48 rex.W
3d: b8 .byte 0xb8


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