[syzbot] [bcachefs?] kernel BUG in bch2_trans_update_by_path (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 02ffd6f89c50 Merge tag 'bpf-fixes' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14789642580000
kernel config: https://syzkaller.appspot.com/x/.config?x=bf99f2510ef92ba5
dashboard link: https://syzkaller.appspot.com/bug?extid=e7b9dfa79acffd3aabdd
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-02ffd6f8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0aa130ecc52/vmlinux-02ffd6f8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3649569ef2fb/bzImage-02ffd6f8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e7b9df...@syzkaller.appspotmail.com

done
bcachefs (loop0): check_alloc_info...
bcachefs (loop0): hole in alloc btree missing in freespace btree
device 0 buckets 25-26, fixing
bcachefs (loop0): bucket incorrectly unset in need_discard btree
u64s 13 type alloc_v4 0:29:0 len 0 ver 0:
gen 0 oldest_gen 0 data_type need_discard
journal_seq_nonempty 1
journal_seq_empty 0
need_discard 1
need_inc_gen 1
dirty_sectors 0
stripe_sectors 0
cached_sectors 0
stripe 0
stripe_redundancy 0
io_time[READ] 1
io_time[WRITE] 1
fragmentation 0
bp_start 8
, fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
device 0 buckets 30-31, fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
device 0 buckets 33-34, fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
device 0 buckets 37-38, fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
device 0 buckets 42-47, fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
device 0 buckets 48-50, fixing
bcachefs (loop0): hole in alloc btree missing in freespace btree
device 0 buckets 51-120, fixing
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 5/128 buckets
done
bcachefs (loop0): check_inodes... done
bcachefs (loop0): resume_logged_ops... done
bcachefs (loop0): delete_dead_inodes... done
bcachefs (loop0): done starting filesystem
bcachefs (loop0): requested incompat feature 1.16: reflink_p_may_update_opts currently not enabled, allowed up to 1.16: reflink_p_may_update_opts
set version_upgrade=incompat to enable
bcachefs (loop0): (disconnected) offset 0: write error: __bch2_write(): insufficient_devices
bcachefs (loop0): pointer to missing indirect extent in (disconnected) offset 0: -4096
u64s 7 type reflink_p 4104:8:U32_MAX len 8 ver 0: idx 0 front_pad 0 back_pad 0
missing reflink btree range 0-8, fixing
------------[ cut here ]------------
kernel BUG at fs/bcachefs/btree_update.c:410!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5358 Comm: syz.0.0 Not tainted syzkaller #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_trans_update_by_path+0x1f2b/0x1f30 fs/bcachefs/btree_update.c:410
Code: fd 90 0f 0b e8 46 86 8f fd 90 0f 0b e8 3e 86 8f fd 90 0f 0b e8 36 86 8f fd 90 0f 0b e8 2e 86 8f fd 90 0f 0b e8 26 86 8f fd 90 <0f> 0b 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3
RSP: 0018:ffffc9000d3c66c8 EFLAGS: 00010283
RAX: ffffffff8430488a RBX: 0000000000004000 RCX: 0000000000100000
RDX: ffffc9000e162000 RSI: 00000000000554a7 RDI: 00000000000554a8
RBP: ffff888055bfa4d8 R08: ffff88800032c880 R09: 0000000000000002
R10: 0000000000000006 R11: 0000000000000002 R12: 0000000000000000
R13: 1ffff1100ab7f49b R14: dffffc0000000000 R15: ffff888055bfa4d8
FS: 00007f461eb3d6c0(0000) GS:ffff88808d00a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f461a1f4fc8 CR3: 0000000043e03000 CR4: 0000000000352ef0
Call Trace:
<TASK>
bch2_trans_update_ip+0x9a6/0x1db0 fs/bcachefs/btree_update.c:531
bch2_trans_update fs/bcachefs/btree_update.h:123 [inline]
bch2_btree_insert_nonextent fs/bcachefs/btree_update.c:625 [inline]
bch2_trans_update_extent fs/bcachefs/btree_update.c:321 [inline]
bch2_trans_update_ip+0x17ef/0x1db0 fs/bcachefs/btree_update.c:503
bch2_trans_update fs/bcachefs/btree_update.h:123 [inline]
bch2_btree_insert_trans+0x1cd/0x330 fs/bcachefs/btree_update.c:637
bch2_indirect_extent_missing_error+0xd2d/0x11b0 fs/bcachefs/reflink.c:239
bch2_lookup_indirect_extent+0x38d/0x5c0 fs/bcachefs/reflink.c:279
trans_trigger_reflink_p_segment fs/bcachefs/reflink.c:308 [inline]
__trigger_reflink_p+0x395/0x19c0 fs/bcachefs/reflink.c:419
bch2_trigger_reflink_p+0x1ea/0x3a0 fs/bcachefs/reflink.c:454
run_one_trans_trigger fs/bcachefs/btree_trans_commit.c:-1 [inline]
bch2_trans_commit_run_triggers fs/bcachefs/btree_trans_commit.c:554 [inline]
__bch2_trans_commit+0xa81/0x8870 fs/bcachefs/btree_trans_commit.c:1023
bch2_trans_commit fs/bcachefs/btree_update.h:241 [inline]
bch2_inode_delete_keys+0x525/0x700 fs/bcachefs/inode.c:1115
bch2_inode_rm+0x282/0x820 fs/bcachefs/inode.c:1146
bch2_evict_inode+0x220/0x520 fs/bcachefs/fs.c:2182
evict+0x504/0x9c0 fs/inode.c:810
__dentry_kill+0x209/0x660 fs/dcache.c:669
dput+0x19f/0x2b0 fs/dcache.c:911
__fput+0x68e/0xa70 fs/file_table.c:476
task_work_run+0x1d1/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f461dd8eba9
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:00007f461eb3d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: fffffffffffffffb RBX: 00007f461dfd5fa0 RCX: 00007f461dd8eba9
RDX: 0000000000141042 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f461de11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f461dfd6038 R14: 00007f461dfd5fa0 R15: 00007fff274d40e8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bch2_trans_update_by_path+0x1f2b/0x1f30 fs/bcachefs/btree_update.c:410
Code: fd 90 0f 0b e8 46 86 8f fd 90 0f 0b e8 3e 86 8f fd 90 0f 0b e8 36 86 8f fd 90 0f 0b e8 2e 86 8f fd 90 0f 0b e8 26 86 8f fd 90 <0f> 0b 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3
RSP: 0018:ffffc9000d3c66c8 EFLAGS: 00010283
RAX: ffffffff8430488a RBX: 0000000000004000 RCX: 0000000000100000
RDX: ffffc9000e162000 RSI: 00000000000554a7 RDI: 00000000000554a8
RBP: ffff888055bfa4d8 R08: ffff88800032c880 R09: 0000000000000002
R10: 0000000000000006 R11: 0000000000000002 R12: 0000000000000000
R13: 1ffff1100ab7f49b R14: dffffc0000000000 R15: ffff888055bfa4d8
FS: 00007f461eb3d6c0(0000) GS:ffff88808d00a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005576da418660 CR3: 0000000043e03000 CR4: 0000000000352ef0


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