[syzbot] [bcachefs?] kernel BUG in bch2_btree_path_traverse_one

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 11066801dd4b Merge tag 'linux_kselftest-fixes-6.12-rc6' of..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=123e755f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=672325e7ab17fdf7
dashboard link: https://syzkaller.appspot.com/bug?extid=997f0573004dcb964555
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=156b2987980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=163e755f980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-11066801.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b062b193560b/vmlinux-11066801.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5b6da4ee7c42/bzImage-11066801.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/8becb7eaabe7/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+997f05...@syzkaller.appspotmail.com

bcachefs (loop0): check_btree_backpointers... done
bcachefs (loop0): check_backpointers_to_extents... done
bcachefs (loop0): check_extents_to_backpointers...
------------[ cut here ]------------
kernel BUG at fs/bcachefs/btree_cache.h:129!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5320 Comm: syz-executor345 Not tainted 6.12.0-rc5-syzkaller-00299-g11066801dd4b #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:bch2_btree_id_root fs/bcachefs/btree_cache.h:129 [inline]
RIP: 0010:btree_path_lock_root fs/bcachefs/btree_iter.c:723 [inline]
RIP: 0010:bch2_btree_path_traverse_one+0x28de/0x2940 fs/bcachefs/btree_iter.c:1183
Code: f4 8e 48 89 de e8 92 da dc 00 e9 78 f8 ff ff e8 38 e1 7b fd 90 0f 0b e8 c0 2d ae 07 e8 2b e1 7b fd 90 0f 0b e8 23 e1 7b fd 90 <0f> 0b e8 1b e1 7b fd 90 0f 0b e8 13 e1 7b fd 90 0f 0b 48 8b 4c 24
RSP: 0018:ffffc9000d0d5de0 EFLAGS: 00010293
RAX: ffffffff8418f8fd RBX: ffff888044480000 RCX: ffff88801f084880
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
RBP: ffffc9000d0d60d0 R08: ffffffff8418e949 R09: ffffffff8418b9a9
R10: 0000000000000002 R11: ffff88801f084880 R12: dffffc0000000000
R13: 0000000000000004 R14: ffff8880414cc380 R15: 0000000000000000
FS: 0000555593398380(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056431d273820 CR3: 0000000044502000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bch2_btree_path_traverse fs/bcachefs/btree_iter.h:247 [inline]
bch2_btree_iter_peek_slot+0x84f/0x2550 fs/bcachefs/btree_iter.c:2629
bch2_backpointer_get_key+0x2bc/0x970 fs/bcachefs/backpointers.c:322
check_bp_exists fs/bcachefs/backpointers.c:579 [inline]
check_extent_to_backpointers+0x21f9/0x46b0 fs/bcachefs/backpointers.c:683
bch2_check_extents_to_backpointers_pass fs/bcachefs/backpointers.c:879 [inline]
bch2_check_extents_to_backpointers+0x1190/0x1bf0 fs/bcachefs/backpointers.c:932
bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:185
bch2_run_recovery_passes+0x387/0x870 fs/bcachefs/recovery_passes.c:232
bch2_fs_recovery+0x25cc/0x39c0 fs/bcachefs/recovery.c:861
bch2_fs_start+0x356/0x5b0 fs/bcachefs/super.c:1036
bch2_fs_get_tree+0xd68/0x1710 fs/bcachefs/fs.c:2170
vfs_get_tree+0x90/0x2b0 fs/super.c:1814
do_new_mount+0x2be/0xb40 fs/namespace.c:3507
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4057 [inline]
__se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
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: 0033:0x7f31be2970aa
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd6f7edc68 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd6f7edc70 RCX: 00007f31be2970aa
RDX: 00000000200058c0 RSI: 0000000020005900 RDI: 00007ffd6f7edc70
RBP: 0000000000000004 R08: 00007ffd6f7edcb0 R09: 00000000000058cb
R10: 0000000000000001 R11: 0000000000000282 R12: 00007ffd6f7edcb0
R13: 0000000000000003 R14: 0000000001000000 R15: 00007f31be2de03b
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bch2_btree_id_root fs/bcachefs/btree_cache.h:129 [inline]
RIP: 0010:btree_path_lock_root fs/bcachefs/btree_iter.c:723 [inline]
RIP: 0010:bch2_btree_path_traverse_one+0x28de/0x2940 fs/bcachefs/btree_iter.c:1183
Code: f4 8e 48 89 de e8 92 da dc 00 e9 78 f8 ff ff e8 38 e1 7b fd 90 0f 0b e8 c0 2d ae 07 e8 2b e1 7b fd 90 0f 0b e8 23 e1 7b fd 90 <0f> 0b e8 1b e1 7b fd 90 0f 0b e8 13 e1 7b fd 90 0f 0b 48 8b 4c 24
RSP: 0018:ffffc9000d0d5de0 EFLAGS: 00010293
RAX: ffffffff8418f8fd RBX: ffff888044480000 RCX: ffff88801f084880
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
RBP: ffffc9000d0d60d0 R08: ffffffff8418e949 R09: ffffffff8418b9a9
R10: 0000000000000002 R11: ffff88801f084880 R12: dffffc0000000000
R13: 0000000000000004 R14: ffff8880414cc380 R15: 0000000000000000
FS: 0000555593398380(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cc391660a8 CR3: 0000000044502000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[syzbot]

syzbot has bisected this issue to:

commit bf4baaa087e2be0279991f1dbf9acaa7a4c9148c
Author: Kent Overstreet <kent.ov...@linux.dev>
Date: Sat Oct 5 21:37:02 2024 +0000

bcachefs: Fix lockdep splat in bch2_accounting_read

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15abcb5f980000
start commit: f1b785f4c787 Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=17abcb5f980000
console output: https://syzkaller.appspot.com/x/log.txt?x=13abcb5f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=1503500c6f615d24
dashboard link: https://syzkaller.appspot.com/bug?extid=997f0573004dcb964555
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16172ce8580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=165214c0580000

Reported-by: syzbot+997f05...@syzkaller.appspotmail.com
Fixes: bf4baaa087e2 ("bcachefs: Fix lockdep splat in bch2_accounting_read")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject:
Author: kent.ov...@linux.dev

#syz fix: bcachefs: Fix btree node scan when unknown btree IDs are present