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

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

Hello,

syzbot found the following issue on:

HEAD commit:    0ad2507d5d93 Linux 6.14-rc3
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13efd7df980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b7bde34acd8f53b1
dashboard link: https://syzkaller.appspot.com/bug?extid=727c886b67040701c448
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-0ad2507d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dfb4fc7c042e/vmlinux-0ad2507d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1682113b81f5/bzImage-0ad2507d.xz

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

loop0: detected capacity change from 0 to 32768
bcachefs (loop0): starting version 1.7: mi_btree_bitmap opts=metadata_checksum=none,data_checksum=none,compression=lz4,erasure_code,fsck,norecovery,nojournal_transaction_names,reconstruct_alloc,nocow,no_data_io
bcachefs (loop0): recovering from clean shutdown, journal seq 10
bcachefs (loop0): Version upgrade required:
Version upgrade from 0.24: unwritten_extents to 1.7: mi_btree_bitmap incomplete
Doing incompatible version upgrade from 0.24: unwritten_extents to 1.20: directory_size
  running recovery passes: check_allocations,check_alloc_info,check_lrus,check_btree_backpointers,check_backpointers_to_extents,check_extents_to_backpointers,check_alloc_to_lru_refs,bucket_gens_init,check_snapshot_trees,check_snapshots,check_subvols,check_subvol_children,delete_dead_snapshots,check_inodes,check_extents,check_indirect_extents,check_dirents,check_xattrs,check_root,check_unreachable_inodes,check_subvolume_structure,check_directory_structure,check_nlinks,set_fs_needs_rebalance
bcachefs (loop0): dropping and reconstructing all alloc info
bcachefs (loop0): error validating btree node on loop0 at btree xattrs level 0/0
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 2285c34bed0abe32 written 16 min_key POS_MIN durability: 1 ptr: 0:31:0 gen 0  
  node offset 0/16 bset u64s 60928: bset past end of btree node (offset 0 len 960 but written 16), exiting
bcachefs (loop0): Unable to continue, halting
bcachefs (loop0): flagging btree xattrs lost data
bcachefs (loop0): running explicit recovery pass check_topology (2), currently at recovery_pass_empty (0)
bcachefs (loop0): running explicit recovery pass scan_for_btree_nodes (1), currently at recovery_pass_empty (0)
error reading btree root btree=xattrs level=0: btree_node_read_error, fixing
invalid bkey in btree_node btree=subvolumes level=0: u64s 7 type subvolume 0:1:0 len 0 ver 0: root 4096 snapshot id 0
  invalid snapshot: delete?, fixing
bcachefs (loop0): scan_for_btree_nodes...
bcachefs (loop0): btree node scan found 7 nodes after overwrites
 done
bcachefs (loop0): check_topology...
bcachefs (loop0): btree root xattrs unreadable, must recover from scan
bcachefs (loop0): bch2_get_scanned_nodes(): recovery btree=xattrs level=0 POS_MIN - SPOS_MAX
bcachefs (loop0): bch2_get_scanned_nodes(): recovering u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 2285c34bed0abe32 written 960 min_key POS_MIN durability: 1 ptr: 0:31:0 gen 0
empty interior btree node at btree=xattrs level=1
u64s 5 type btree_ptr SPOS_MAX len 0 ver 0, fixing
bcachefs (loop0): empty btree root xattrs
 done
bcachefs (loop0): accounting_read... done
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: 0 PID: 5320 at kernel/locking/lockdep.c:234 hlock_class kernel/locking/lockdep.c:234 [inline]
WARNING: CPU: 0 PID: 5320 at kernel/locking/lockdep.c:234 check_wait_context kernel/locking/lockdep.c:4852 [inline]
WARNING: CPU: 0 PID: 5320 at kernel/locking/lockdep.c:234 __lock_acquire+0x564/0x2100 kernel/locking/lockdep.c:5178
Modules linked in:
CPU: 0 UID: 0 PID: 5320 Comm: syz.0.0 Not tainted 6.14.0-rc3-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
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 21 60 a0 0e 00 75 23 90 48 c7 c7 40 a2 2a 8c 48 c7 c6 40 a5 2a 8c e8 97 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:ffffc9000d4df530 EFLAGS: 00010046
RAX: 95b5ba76c7869700 RBX: 0000000000000c41 RCX: 0000000000100000
RDX: dffffc0000000000 RSI: 000000000005bf76 RDI: 000000000005bf77
RBP: 0000000000040c41 R08: ffffffff81817e32 R09: 1ffff11003f8519a
R10: dffffc0000000000 R11: ffffed1003f8519b R12: ffff8880009cd354
R13: 0000000000000005 R14: 1ffff11000139a77 R15: ffff8880009cd3b8
FS:  00007f48caa6a6c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562b40d2b088 CR3: 00000000408fe000 CR4: 0000000000352ef0
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: 0033:0x7f48c9b8e58a
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:00007f48caa69e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f48caa69ef0 RCX: 00007f48c9b8e58a
RDX: 00004000000058c0 RSI: 0000400000005900 RDI: 00007f48caa69eb0
RBP: 00004000000058c0 R08: 00007f48caa69ef0 R09: 0000000000010000
R10: 0000000000010000 R11: 0000000000000246 R12: 0000400000005900
R13: 00007f48caa69eb0 R14: 0000000000005912 R15: 00004000000001c0
 </TASK>


---
This report 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 syzkaller@googlegroups.com.

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

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup