linux-kernel - [syzbot] [bcachefs?] kernel BUG in bch2_inode_update_after

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Message-ID: <680001d8.050a0220.5cdb3.0008.GAE@google.com>
Date: Wed, 16 Apr 2025 12:15:36 -0700
From: syzbot <syzbot+af878a66b6ed801e9515@...kaller.appspotmail.com>
To: kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] kernel BUG in bch2_inode_update_after_write (2)

Hello,

syzbot found the following issue on:

HEAD commit:    834a4a689699 Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1757c470580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a972ee73c2fcf8ca
dashboard link: https://syzkaller.appspot.com/bug?extid=af878a66b6ed801e9515
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-834a4a68.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4454365a3050/vmlinux-834a4a68.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2d99dbd9f6f4/bzImage-834a4a68.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+af878a66b6ed801e9515@...kaller.appspotmail.com

bcachefs (loop0): accounting_read... done
bcachefs (loop0): alloc_read... done
bcachefs (loop0): snapshots_read...
bcachefs (loop0): running explicit recovery pass reconstruct_snapshots (21), currently at snapshots_read (7)
 done
bcachefs (loop0): check_allocations...
bcachefs (loop0): btree ptr not marked in member info btree allocated bitmap
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq ac62141f8dc7e261 written 24 min_key POS_MIN durability: 1 ptr: 0:26:0 gen 0, fixing
bcachefs (loop0): bucket 0:26 data type btree ptr gen 0 missing in alloc btree
  while marking u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq ac62141f8dc7e261 written 24 min_key POS_MIN durability: 1 ptr: 0:26:0 gen 0, fixing
bcachefs (loop0): btree ptr not marked in member info btree allocated bitmap
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 7589ab5e0c11cc7a written 24 min_key POS_MIN durability: 1 ptr: 0:38:0 gen 0, fixing
bcachefs (loop0): btree ptr not marked in member info btree allocated bitmap
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 9aa2895aefce4bdf written 24 min_key POS_MIN durability: 1 ptr: 0:41:0 gen 0, fixing
bcachefs (loop0): btree ptr not marked in member info btree allocated bitmap
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq c0bef60d07ceb940 written 16 min_key POS_MIN durability: 1 ptr: 0:35:0 gen 0, fixing
bcachefs (loop0): btree ptr not marked in member info btree allocated bitmap
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq e81e1ed936acf3df written 32 min_key POS_MIN durability: 1 ptr: 0:29:0 gen 0, fixing
bcachefs (loop0): bucket 0:15 gen 0 has wrong data_type: got free, should be journal, fixing
bcachefs (loop0): bucket 0:15 gen 0 data type journal has wrong dirty_sectors: got 0, should be 256, fixing
bcachefs (loop0): bucket 0:26 gen 0 has wrong data_type: got free, should be btree, fixing
bcachefs (loop0): bucket 0:26 gen 0 data type btree has wrong dirty_sectors: got 0, should be 256, fixing
bcachefs (loop0): bucket 0:32 gen 0 has wrong data_type: got btree, should be need_discard, fixing
bcachefs (loop0): bucket 0:32 gen 0 data type need_discard has wrong dirty_sectors: got 256, should be 0, fixing
 done
bcachefs (loop0): going read-write
bcachefs (loop0): journal_replay... done
bcachefs (loop0): check_lrus... done
bcachefs (loop0): check_backpointers_to_extents... done
bcachefs (loop0): check_extents_to_backpointers...
bcachefs (loop0): scanning for missing backpointers in 4/128 buckets
 done
bcachefs (loop0): reconstruct_snapshots...
bcachefs (loop0): snapshot node 4294967295 from tree 4294967295 missing, recreating
 done
bcachefs (loop0): check_inodes... done
bcachefs (loop0): resume_logged_ops... done
bcachefs (loop0): delete_dead_inodes... done
bcachefs (loop0): Fixed errors, running fsck a second time to verify fs is clean
bcachefs (loop0): check_lrus... done
bcachefs (loop0): check_backpointers_to_extents... done
bcachefs (loop0): check_extents_to_backpointers...
bcachefs (loop0): scanning for missing backpointers in 1/128 buckets
 done
bcachefs (loop0): reconstruct_snapshots... done
bcachefs (loop0): check_inodes... done
bcachefs (loop0): resume_logged_ops... done
bcachefs (loop0): delete_dead_inodes... done
bcachefs (loop0): done starting filesystem
------------[ cut here ]------------
kernel BUG at fs/bcachefs/fs.c:61!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5325 Comm: syz.0.0 Not tainted 6.15.0-rc2-syzkaller-00037-g834a4a689699 #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_inode_update_after_write+0xc89/0xc90 fs/bcachefs/fs.c:61
Code: ff 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c cc fb ff ff 48 89 f7 49 89 f6 e8 25 5c bc fd 4c 89 f6 e9 b9 fb ff ff e8 08 23 52 fd 90 <0f> 0b e8 d0 8e bf 07 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000d4d78c0 EFLAGS: 00010293
RAX: ffffffff84713228 RBX: 000000000000100c RCX: ffff888000e1c880
RDX: 0000000000000000 RSI: 000000000000100c RDI: 0000000000001002
RBP: ffffc9000d4d7a10 R08: ffffffff847126c2 R09: 00000000ffffffff
R10: 0000000000001000 R11: 00000000ffffffff R12: 0000000000001002
R13: ffff888043ff9e60 R14: ffff888043ff9e60 R15: ffffc9000d4d7b90
FS:  00007f76e17e76c0(0000) GS:ffff88808c593000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002bc0 CR3: 0000000041356000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __bch2_unlink+0x459/0x520 fs/bcachefs/fs.c:818
 bch2_unlink+0xac/0xf0 fs/bcachefs/fs.c:841
 vfs_unlink+0x365/0x650 fs/namei.c:4544
 do_unlinkat+0x442/0x7b0 fs/namei.c:4608
 __do_sys_unlink fs/namei.c:4654 [inline]
 __se_sys_unlink fs/namei.c:4652 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:4652
 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: 0033:0x7f76e098d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007f76e17e7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007f76e0ba5fa0 RCX: 00007f76e098d169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000500
RBP: 00007f76e0a0e990 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f76e0ba5fa0 R15: 00007fff9e387278
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bch2_inode_update_after_write+0xc89/0xc90 fs/bcachefs/fs.c:61
Code: ff 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c cc fb ff ff 48 89 f7 49 89 f6 e8 25 5c bc fd 4c 89 f6 e9 b9 fb ff ff e8 08 23 52 fd 90 <0f> 0b e8 d0 8e bf 07 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000d4d78c0 EFLAGS: 00010293
RAX: ffffffff84713228 RBX: 000000000000100c RCX: ffff888000e1c880
RDX: 0000000000000000 RSI: 000000000000100c RDI: 0000000000001002
RBP: ffffc9000d4d7a10 R08: ffffffff847126c2 R09: 00000000ffffffff
R10: 0000000000001000 R11: 00000000ffffffff R12: 0000000000001002
R13: ffff888043ff9e60 R14: ffff888043ff9e60 R15: ffffc9000d4d7b90
FS:  00007f76e17e76c0(0000) GS:ffff88808c593000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002bc0 CR3: 0000000041356000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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