[syzbot] [bcachefs?] kernel BUG in __bch2_str_hash_check_key

[syzbot <syzbot+843981bb836d699c07d1@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    56f944529ec2 Merge tag 'input-for-v6.15-rc0' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16391fb0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f2054704dd53fb80
dashboard link: https://syzkaller.appspot.com/bug?extid=843981bb836d699c07d1
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-56f94452.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c6da83e5191b/vmlinux-56f94452.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5c060438ea13/bzImage-56f94452.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+843981bb836d699c07d1@syzkaller.appspotmail.com

    bi_dir=4096
    bi_dir_offset=5682031293254759865
    bi_subvol=0
    bi_parent_subvol=0
    bi_nocow=0
    bi_depth=0
    bi_inodes_32bit=0, fixing
bcachefs (loop0): inode points to missing dirent
  inum: 4099:4294967295 
    mode=100755
    flags=(15300000)
    journal_seq=5
    hash_seed=ab878b4c5ab7c89e
    hash_type=siphash
    bi_size=1050
    bi_sectors=8
    bi_version=0
    bi_atime=1997793410
    bi_ctime=1997793410
    bi_mtime=1997793410
    bi_otime=1997793410
    bi_uid=0
    bi_gid=0
    bi_nlink=0
    bi_generation=0
    bi_dev=0
    bi_data_checksum=0
    bi_compression=0
    bi_project=0
    bi_background_compression=0
    bi_data_replicas=0
    bi_promote_target=0
    bi_foreground_target=0
    bi_background_target=0
    bi_erasure_code=0
    bi_fields_set=0
    bi_dir=4098
    bi_dir_offset=2566586984702133180
    bi_subvol=0
    bi_parent_subvol=0
    bi_nocow=0
    bi_depth=0
    bi_inodes_32bit=0, fixing
 done
bcachefs (loop0): check_dirents...
bcachefs (loop0): hash table key at wrong offset: btree dirents inode 4096 offset 6229884513039707068, hashed to 5410109479790105297
  u64s 7 type dirent 4096:6229884513039707068:U32_MAX len 0 ver 0: �˨� -> 2166030336 -> 1073741825 type subvol, fixing
bcachefs (loop0): hash table key at wrong offset: btree dirents inode 4096 offset 6229884513039707068, hashed to 5410109479790105297
  u64s 7 type dirent 4096:6229884513039707068:U32_MAX len 0 ver 0: �˨� -> 2166030336 -> 1073741825 type subvol, fixing
------------[ cut here ]------------
kernel BUG at fs/bcachefs/fsck.c:954!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5328 Comm: syz.0.0 Not tainted 6.14.0-syzkaller-13443-g56f944529ec2 #0 PREEMPT(full) 
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_fsck_update_backpointers+0x4ed/0x4f0 fs/bcachefs/fsck.c:954
Code: e9 2b fc ff ff 89 d9 80 e1 07 38 c1 0f 8c 62 fc ff ff 48 89 df e8 63 77 b7 fd e9 55 fc ff ff e8 39 78 ba 07 e8 74 4e 4d fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e
RSP: 0018:ffffc9000d4ce460 EFLAGS: 00010246
RAX: ffffffff847608cc RBX: 0000000000000010 RCX: 0000000000100000
RDX: ffffc9000e50a000 RSI: 00000000000fffff RDI: 0000000000100000
RBP: ffffc9000d4ce600 R08: ffffffff84760529 R09: 0000000000000000
R10: ffffc9000d4ce530 R11: fffff52001a99caf R12: ffffc9000d4cf290
R13: dffffc0000000000 R14: ffff888052bda000 R15: ffff888052900000
FS:  00007f5be4f2b6c0(0000) GS:ffff88808c596000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b32eddc088 CR3: 0000000044eda000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __bch2_str_hash_check_key+0x202c/0x3b50 fs/bcachefs/str_hash.c:257
 bch2_str_hash_check_key fs/bcachefs/str_hash.h:415 [inline]
 check_dirent fs/bcachefs/fsck.c:2135 [inline]
 bch2_check_dirents+0x2d45/0x3b90 fs/bcachefs/fsck.c:2230
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:285
 bch2_fs_recovery+0x292a/0x3e20 fs/bcachefs/recovery.c:936
 bch2_fs_start+0x310/0x620 fs/bcachefs/super.c:1069
 bch2_fs_get_tree+0x113e/0x18f0 fs/bcachefs/fs.c:2253
 vfs_get_tree+0x90/0x2b0 fs/super.c:1759
 do_new_mount+0x2cf/0xb70 fs/namespace.c:3879
 do_mount fs/namespace.c:4219 [inline]
 __do_sys_mount fs/namespace.c:4430 [inline]
 __se_sys_mount+0x38c/0x400 fs/namespace.c:4407
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5be418e90a
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:00007f5be4f2ae68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5be4f2aef0 RCX: 00007f5be418e90a
RDX: 000020000000f640 RSI: 0000200000000140 RDI: 00007f5be4f2aeb0
RBP: 000020000000f640 R08: 00007f5be4f2aef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000140
R13: 00007f5be4f2aeb0 R14: 000000000000f61b R15: 0000200000000340
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bch2_fsck_update_backpointers+0x4ed/0x4f0 fs/bcachefs/fsck.c:954
Code: e9 2b fc ff ff 89 d9 80 e1 07 38 c1 0f 8c 62 fc ff ff 48 89 df e8 63 77 b7 fd e9 55 fc ff ff e8 39 78 ba 07 e8 74 4e 4d fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e
RSP: 0018:ffffc9000d4ce460 EFLAGS: 00010246
RAX: ffffffff847608cc RBX: 0000000000000010 RCX: 0000000000100000
RDX: ffffc9000e50a000 RSI: 00000000000fffff RDI: 0000000000100000
RBP: ffffc9000d4ce600 R08: ffffffff84760529 R09: 0000000000000000
R10: ffffc9000d4ce530 R11: fffff52001a99caf R12: ffffc9000d4cf290
R13: dffffc0000000000 R14: ffff888052bda000 R15: ffff888052900000
FS:  00007f5be4f2b6c0(0000) GS:ffff88808c596000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b32eddc088 CR3: 0000000044eda000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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