syzbot


WARNING in __btrfs_update_delayed_inode (4)

Status: upstream: reported on 2026/04/24 07:54
Subsystems: btrfs
[Documentation on labels]
Reported-by: syzbot+768687d6d7c96a124e24@syzkaller.appspotmail.com
First crash: 5d15h, last: 5d15h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [btrfs?] WARNING in __btrfs_update_delayed_inode (4) 1 (2) 2026/04/24 14:13
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in __btrfs_update_delayed_inode btrfs -1 2 1153d 1154d 0/29 auto-obsoleted due to no activity on 2023/06/27 15:17
upstream WARNING in __btrfs_update_delayed_inode (2) btrfs -1 2 407d 444d 0/29 auto-obsoleted due to no activity on 2025/06/22 17:49
upstream WARNING in __btrfs_update_delayed_inode (3) btrfs -1 1 133d 129d 0/29 auto-obsoleted due to no activity on 2026/03/23 08:26

Sample crash report:
------------[ cut here ]------------
BTRFS: Transaction aborted (error -28)
WARNING: fs/btrfs/delayed-inode.c:1027 at __btrfs_update_delayed_inode+0xe3d/0x1070 fs/btrfs/delayed-inode.c:1027, CPU#0: kworker/u4:5/70
Modules linked in:
CPU: 0 UID: 0 PID: 70 Comm: kworker/u4:5 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: events_unbound btrfs_async_reclaim_data_space
RIP: 0010:__btrfs_update_delayed_inode+0xe40/0x1070 fs/btrfs/delayed-inode.c:1027
Code: bc bd fd e9 22 01 00 00 e8 7d d1 a2 fd 84 c0 74 23 e8 a4 bc bd fd e9 0f 01 00 00 e8 9a bc bd fd 48 8d 3d 63 e8 34 0c 44 89 ee <67> 48 0f b9 3a e9 31 01 00 00 e8 51 38 b1 07 89 c3 31 ff 89 c6 e8
RSP: 0018:ffffc90000cff140 EFLAGS: 00010293
RAX: ffffffff84082226 RBX: 00000000ffffffe4 RCX: ffff888000bc4a00
RDX: 0000000000000000 RSI: 00000000ffffffe4 RDI: ffffffff903d0a90
RBP: ffffc90000cff270 R08: ffff888000bc4a00 R09: 0000000000000003
R10: 00000000fffffffb R11: 0000000000000000 R12: ffff888011cf9200
R13: 00000000ffffffe4 R14: 0000000000000000 R15: ffff888012ef93c0
FS:  0000000000000000(0000) GS:ffff88808c812000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4b4adeaff8 CR3: 000000001f399000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1103 [inline]
 __btrfs_commit_inode_delayed_items+0x1dfa/0x1f50 fs/btrfs/delayed-inode.c:1127
 __btrfs_run_delayed_items+0x1f6/0x510 fs/btrfs/delayed-inode.c:1158
 btrfs_commit_transaction+0x836/0x30e0 fs/btrfs/transaction.c:2376
 flush_space+0x2a3/0xe20 fs/btrfs/space-info.c:-1
 do_async_reclaim_data_space+0x29a/0x520 fs/btrfs/space-info.c:1464
 btrfs_async_reclaim_data_space+0x41/0x90 fs/btrfs/space-info.c:1512
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	bc bd fd e9 22       	mov    $0x22e9fdbd,%esp
   5:	01 00                	add    %eax,(%rax)
   7:	00 e8                	add    %ch,%al
   9:	7d d1                	jge    0xffffffdc
   b:	a2 fd 84 c0 74 23 e8 	movabs %al,0xbca4e82374c084fd
  12:	a4 bc
  14:	bd fd e9 0f 01       	mov    $0x10fe9fd,%ebp
  19:	00 00                	add    %al,(%rax)
  1b:	e8 9a bc bd fd       	call   0xfdbdbcba
  20:	48 8d 3d 63 e8 34 0c 	lea    0xc34e863(%rip),%rdi        # 0xc34e88a
  27:	44 89 ee             	mov    %r13d,%esi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 31 01 00 00       	jmp    0x165
  34:	e8 51 38 b1 07       	call   0x7b1388a
  39:	89 c3                	mov    %eax,%ebx
  3b:	31 ff                	xor    %edi,%edi
  3d:	89 c6                	mov    %eax,%esi
  3f:	e8                   	.byte 0xe8

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/20 07:47 upstream bea8d77e45a8 303e2802 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
* Struck through repros no longer work on HEAD.