Subject: WARNING in mark_lock (2)

From: syzbot <[email-masked]>
Date: Tue, 24 Sep 2019 01:06:06 -0700

Hello,

syzbot found the following crash on:

HEAD commit:    b41dae06 Merge tag 'xfs-5.4-merge-7' of git://git.kernel.o..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16b6d8e9600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dfcf592db22b9132
dashboard link: https://syzkaller.appspot.com/bug?extid=ef8a7c8214359d969c69
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: [email-masked]

------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(1)
WARNING: CPU: 1 PID: 20740 at kernel/locking/lockdep.c:167 hlock_class  
kernel/locking/lockdep.c:167 [inline]
WARNING: CPU: 1 PID: 20740 at kernel/locking/lockdep.c:167 hlock_class  
kernel/locking/lockdep.c:156 [inline]
WARNING: CPU: 1 PID: 20740 at kernel/locking/lockdep.c:167  
mark_lock+0x22b/0x1220 kernel/locking/lockdep.c:3643
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 20740 Comm: kworker/u4:10 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  panic+0x2dc/0x755 kernel/panic.c:219
  __warn.cold+0x20/0x4c kernel/panic.c:576
  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+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:hlock_class kernel/locking/lockdep.c:167 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:156 [inline]
RIP: 0010:mark_lock+0x22b/0x1220 kernel/locking/lockdep.c:3643
Code: d0 7c 08 84 d2 0f 85 a8 0e 00 00 44 8b 1d 9d 6d 6e 08 45 85 db 75 b6  
48 c7 c6 a0 26 ac 87 48 c7 c7 e0 26 ac 87 e8 2d 79 eb ff <0f> 0b 31 db e9  
aa fe ff ff 48 c7 c7 e0 60 ae 8a e8 30 8e 54 00 e9
RSP: 0018:ffff88805d72f8d8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815c26d6 RDI: ffffed100bae5f0d
RBP: ffff88805d72f928 R08: ffff88806aefa480 R09: fffffbfff11f40b9
R10: fffffbfff11f40b8 R11: ffffffff88fa05c3 R12: 0000000000000008
R13: ffff88806aefad68 R14: 0000000000000000 R15: 00000000000c095a
  mark_usage kernel/locking/lockdep.c:3592 [inline]
  __lock_acquire+0x538/0x4e70 kernel/locking/lockdep.c:3909
  lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4487
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159
  __wake_up_common_lock+0xc8/0x150 kernel/sched/wait.c:122
  __wake_up+0xe/0x10 kernel/sched/wait.c:142
  finish_writeback_work.isra.0+0xf6/0x120 fs/fs-writeback.c:168
  wb_do_writeback fs/fs-writeback.c:2030 [inline]
  wb_workfn+0x34f/0x11e0 fs/fs-writeback.c:2070
  process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
  worker_thread+0x98/0xe40 kernel/workqueue.c:2415
  kthread+0x361/0x430 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..

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