general protection fault in klist_iter_exit

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 66722c42ec91 Linux 4.14.256
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14007fb2b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=b8004ce84f364d9
dashboard link: https://syzkaller.appspot.com/bug?extid=8bed1c10e381002a5ecb
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8bed1c...@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: 0 PID: 9169 Comm: kworker/0:4 Not tainted 4.14.256-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events netlink_sock_destruct_work
task: ffff8880992b8200 task.stack: ffff888099260000
RIP: 0010:klist_iter_exit+0x21/0x80 lib/klist.c:314
RSP: 0018:ffff888099267c80 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000040173
R10: ffff8880992b8ad8 R11: ffff8880992b8200 R12: 0000000000000000
R13: ffffffff88724a60 R14: ffff8880ba433b00 R15: ffff8880ba438000
FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f42687aa906 CR3: 000000009ec42000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
nfc_device_iter_exit net/nfc/nfc.h:133 [inline]
nfc_genl_dump_devices_done+0x31/0x50 net/nfc/netlink.c:669
genl_lock_done+0x82/0xc0 net/netlink/genetlink.c:494
netlink_sock_destruct+0x8b/0x250 net/netlink/af_netlink.c:366
__sk_destruct+0x49/0x760 net/core/sock.c:1574
sk_destruct net/core/sock.c:1615 [inline]
__sk_free+0xd9/0x2d0 net/core/sock.c:1623
sk_free+0x2b/0x40 net/core/sock.c:1634
process_one_work+0x793/0x14a0 kernel/workqueue.c:2117
worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: ff 66 0f 1f 84 00 00 00 00 00 41 54 55 53 48 89 fb e8 04 bc 57 fa 48 8d 6b 08 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 <80> 3c 02 00 75 40 4c 8b 63 08 4d 85 e4 74 2e e8 db bb 57 fa 31
RIP: klist_iter_exit+0x21/0x80 lib/klist.c:314 RSP: ffff888099267c80
---[ end trace 0fccd39209cdc354 ]---
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
7: 00 00
9: 41 54 push %r12
b: 55 push %rbp
c: 53 push %rbx
d: 48 89 fb mov %rdi,%rbx
10: e8 04 bc 57 fa callq 0xfa57bc19
15: 48 8d 6b 08 lea 0x8(%rbx),%rbp
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 48 89 ea mov %rbp,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 75 40 jne 0x70
30: 4c 8b 63 08 mov 0x8(%rbx),%r12
34: 4d 85 e4 test %r12,%r12
37: 74 2e je 0x67
39: e8 db bb 57 fa callq 0xfa57bc19
3e: 31 .byte 0x31


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[syzbot]

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