WARNING in zap_class

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: c63e9e91a254 Add linux-next specific files for 20190301
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1619d157200000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5875f9dc6e009b2
dashboard link: https://syzkaller.appspot.com/bug?extid=cf2bf6c32e9043f22ad1
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+cf2bf6...@syzkaller.appspotmail.com

WARNING: CPU: 1 PID: 5034 at kernel/locking/lockdep.c:4539
remove_class_from_lock_chain kernel/locking/lockdep.c:4519 [inline]
WARNING: CPU: 1 PID: 5034 at kernel/locking/lockdep.c:4539
remove_class_from_lock_chains kernel/locking/lockdep.c:4559 [inline]
WARNING: CPU: 1 PID: 5034 at kernel/locking/lockdep.c:4539
zap_class+0x741/0xe20 kernel/locking/lockdep.c:4598
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 5034 Comm: kworker/1:6 Not tainted 5.0.0-rc8-next-20190301 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events pwq_unbound_release_workfn
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
panic+0x2cb/0x65c kernel/panic.c:214
__warn.cold+0x20/0x45 kernel/panic.c:571
report_bug+0x263/0x2b0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:remove_class_from_lock_chain kernel/locking/lockdep.c:4539
[inline]
RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:4559
[inline]
RIP: 0010:zap_class+0x741/0xe20 kernel/locking/lockdep.c:4598
Code: 0f b6 14 38 4c 89 e0 83 e0 07 83 c0 01 38 d0 0f 8c 79 ff ff ff 84 d2
0f 84 71 ff ff ff 4c 89 e7 e8 d4 f3 51 00 e9 64 ff ff ff <0f> 0b e8 08 93
d6 01 e9 4e fb ff ff 48 89 55 c0 4c 89 4d c8 e8 f6
RSP: 0018:ffff8880a07afc10 EFLAGS: 00010012
RAX: 0000000000010000 RBX: 6342c11cd9299b1b RCX: ffffffff832f401e
RDX: 00000000000066dd RSI: ffffffff832f406a RDI: 0000000000000006
RBP: ffff8880a07afc68 R08: ffff88804b968180 R09: ffffffff8a0a1dc8
R10: 00000000002e0a57 R11: 000000000a570a56 R12: ffffffff89c662c8
R13: 0000000000000000 R14: ffffffff89c662c0 R15: dffffc0000000000
__lockdep_free_key_range+0x64/0x120 kernel/locking/lockdep.c:4721
lockdep_unregister_key+0x201/0x4c0 kernel/locking/lockdep.c:4917
wq_unregister_lockdep kernel/workqueue.c:3453 [inline]
pwq_unbound_release_workfn+0x233/0x2f0 kernel/workqueue.c:3673
process_one_work+0x98e/0x1790 kernel/workqueue.c:2269
worker_thread+0x98/0xe40 kernel/workqueue.c:2415
kthread+0x357/0x430 kernel/kthread.c:253
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.

[Dmitry Vyukov]

#syz upstream

> --
> You received this message because you are subscribed to the Google Groups "syzkaller-upstream-moderation" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-upstream-m...@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-upstream-moderation/000000000000f108b5058347fe3b%40google.com.
> For more options, visit https://groups.google.com/d/optout.