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Date:   Sat, 21 Oct 2023 19:40:53 -0700
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Subject: [syzbot] [btrfs?] BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! (4)
From:   syzbot <syzbot+b2869947e0c9467a41b6@syzkaller.appspotmail.com>
To:     clm@fb.com, dsterba@suse.com, josef@toxicpanda.com,
        linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
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Hello,

syzbot found the following issue on:

HEAD commit:    78124b0c1d10 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=1557da89680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f27cd6e68911e026
dashboard link: https://syzkaller.appspot.com/bug?extid=b2869947e0c9467a41b6
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=137ac45d680000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16e4640b680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bd512de820ae/disk-78124b0c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a47a437b1d4f/vmlinux-78124b0c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3ae8b966bcd7/Image-78124b0c.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/d5d514495f15/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b2869947e0c9467a41b6@syzkaller.appspotmail.com

BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!
turning off the locking correctness validator.
CPU: 0 PID: 5571 Comm: kworker/u4:8 Not tainted 6.6.0-rc6-syzkaller-g78124b0c1d10 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: btrfs-cache btrfs_work_helper
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233
 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 dump_stack+0x1c/0x28 lib/dump_stack.c:113
 lookup_chain_cache_add kernel/locking/lockdep.c:3815 [inline]
 validate_chain kernel/locking/lockdep.c:3836 [inline]
 __lock_acquire+0x1c60/0x75e8 kernel/locking/lockdep.c:5136
 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5753
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 __clear_extent_bit+0x1b4/0xaf0 fs/btrfs/extent-io-tree.c:596
 clear_extent_bit fs/btrfs/extent-io-tree.h:146 [inline]
 clear_extent_bits fs/btrfs/extent-io-tree.h:158 [inline]
 btrfs_free_excluded_extents fs/btrfs/block-group.c:840 [inline]
 caching_thread+0x18bc/0x1b64 fs/btrfs/block-group.c:909
 btrfs_work_helper+0x340/0x1504 fs/btrfs/async-thread.c:314
 process_one_work+0x694/0x1204 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x938/0xef4 kernel/workqueue.c:2784
 kthread+0x288/0x310 kernel/kthread.c:388
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:857
BTRFS info (device loop0): qgroup scan completed (inconsistency flag cleared)
BTRFS info (device loop0): qgroup scan completed (inconsistency flag cleared)
BTRFS info (device loop0): qgroup scan completed (inconsistency flag cleared)


---
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