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kernel BUG in bch2_trans_update_by_path (2)

Status: upstream: reported on 2025/09/12 07:06
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+e7b9dfa79acffd3aabdd@syzkaller.appspotmail.com
First crash: 1d03h, last: 22h26m
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] kernel BUG in bch2_trans_update_by_path (2) 0 (1) 2025/09/12 07:06
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream kernel BUG in bch2_trans_update_by_path bcachefs -1 C done 857 10d 85d 29/29 fixed on 2025/09/04 16:57

Sample crash report:
 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

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/12 03:14 upstream 02ffd6f89c50 e2beed91 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_trans_update_by_path
2025/09/11 22:16 upstream 02ffd6f89c50 e2beed91 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in bch2_trans_update_by_path
* Struck through repros no longer work on HEAD.