Re: [syzbot] [bcachefs] WARNING: locking bug in simple_recursive_removal

[syzbot <syzbot+727c886b67040701c448@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    2408a807bfc3 Merge tag 'vfs-6.14-rc4.fixes' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=154fb7df980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6cc40dfe827ffb85
dashboard link: https://syzkaller.appspot.com/bug?extid=727c886b67040701c448
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17982498580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3bbfce004a48/disk-2408a807.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0151460c5539/vmlinux-2408a807.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8dfe7f8b2862/bzImage-2408a807.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/2e6491f4c19e/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+727c886b67040701c448@syzkaller.appspotmail.com

bcachefs (loop0): alloc_read... done
bcachefs (loop0): stripes_read... done
bcachefs (loop0): snapshots_read... done
bcachefs (loop0): done starting filesystem
bcachefs (loop0): missing subvolume 1
bcachefs (loop0): inconsistency detected - emergency read only at journal seq 10
bcachefs (loop0): bch2_fs_get_tree(): error mounting: error getting root inode ENOENT_bkey_type_mismatch
bcachefs (loop0): shutting down
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(1)
WARNING: CPU: 1 PID: 6056 at kernel/locking/lockdep.c:234 hlock_class kernel/locking/lockdep.c:234 [inline]
WARNING: CPU: 1 PID: 6056 at kernel/locking/lockdep.c:234 check_wait_context kernel/locking/lockdep.c:4852 [inline]
WARNING: CPU: 1 PID: 6056 at kernel/locking/lockdep.c:234 __lock_acquire+0x564/0x2100 kernel/locking/lockdep.c:5178
Modules linked in:
CPU: 1 UID: 0 PID: 6056 Comm: syz.0.18 Not tainted 6.14.0-rc3-syzkaller-00012-g2408a807bfc3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4852 [inline]
RIP: 0010:__lock_acquire+0x564/0x2100 kernel/locking/lockdep.c:5178
Code: 00 00 83 3d 81 37 9f 0e 00 75 23 90 48 c7 c7 e0 a2 2a 8c 48 c7 c6 e0 a5 2a 8c e8 07 c2 e4 ff 48 ba 00 00 00 00 00 fc ff df 90 <0f> 0b 90 90 90 31 db 48 81 c3 c4 00 00 00 48 89 d8 48 c1 e8 03 0f
RSP: 0018:ffffc90003337530 EFLAGS: 00010046
RAX: 8841e1c411249300 RBX: 0000000000001826 RCX: ffff8880278ebc00
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000041826 R08: ffffffff81817d42 R09: 1ffff110170e519a
R10: dffffc0000000000 R11: ffffed10170e519b R12: ffff8880278ec6d4
R13: 0000000000000005 R14: 1ffff11004f1d8e7 R15: ffff8880278ec738
FS:  00007efc242d26c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055efac1c6518 CR3: 000000006cff8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 down_write+0x99/0x220 kernel/locking/rwsem.c:1577
 inode_lock include/linux/fs.h:877 [inline]
 simple_recursive_removal+0x9a/0x8f0 fs/libfs.c:615
 debugfs_remove+0x49/0x70 fs/debugfs/inode.c:805
 __bch2_fs_stop+0x290/0x5c0 fs/bcachefs/super.c:643
 bch2_fs_get_tree+0xd3a/0x17a0 fs/bcachefs/fs.c:2303
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3560
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efc2338e58a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efc242d1e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007efc242d1ef0 RCX: 00007efc2338e58a
RDX: 00004000000058c0 RSI: 0000400000005900 RDI: 00007efc242d1eb0
RBP: 00004000000058c0 R08: 00007efc242d1ef0 R09: 0000000000010000
R10: 0000000000010000 R11: 0000000000000246 R12: 0000400000005900
R13: 00007efc242d1eb0 R14: 0000000000005912 R15: 00004000000001c0
 </TASK>


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