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Date:   Sun, 20 Oct 2019 16:33:11 -0700
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Subject: Re: BUG: MAX_LOCKDEP_CHAINS too low!
From:   syzbot <syzbot+aaa6fa4949cc5d9b7b25@syzkaller.appspotmail.com>
To:     dvyukov@google.com, linux-kernel@vger.kernel.org, mingo@kernel.org,
        peterz@infradead.org, syzkaller-bugs@googlegroups.com,
        tglx@linutronix.de, will.deacon@arm.com
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syzbot has found a reproducer for the following crash on:

HEAD commit:    4fe34d61 Merge branch 'x86-urgent-for-linus' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1176cd40e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e0ac4d9b35046343
dashboard link: https://syzkaller.appspot.com/bug?extid=aaa6fa4949cc5d9b7b25
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14150b40e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e122ff600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+aaa6fa4949cc5d9b7b25@syzkaller.appspotmail.com

BUG: MAX_LOCKDEP_CHAINS too low!
turning off the locking correctness validator.
CPU: 0 PID: 11772 Comm: kworker/u5:486 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: hci1600 hci_power_on
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
  add_chain_cache kernel/locking/lockdep.c:2816 [inline]
  lookup_chain_cache_add kernel/locking/lockdep.c:2915 [inline]
  validate_chain kernel/locking/lockdep.c:2936 [inline]
  __lock_acquire.cold+0x325/0x385 kernel/locking/lockdep.c:3955
  lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4487
  process_one_work+0x91c/0x1740 kernel/workqueue.c:2245
  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