WARNING in __btrfs_update_delayed_inode (4)

Status: upstream: reported on 2026/04/24 07:54
Subsystems: btrfs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+768687d6d7c96a124e24@syzkaller.appspotmail.com
First crash: 155d, last: 7d13h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
d8936ba7 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in __btrfs_update_delayed_inode (4) 2026/05/19 01:17 2026/05/19 01:17 2026/05/19 01:57 9f74d399
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly btrfs report (Sep 2026) 0 (1) 2026/09/04 20:33
[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 1303d 1304d 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 556d 594d 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 283d 279d 0/29 auto-obsoleted due to no activity on 2026/03/23 08:26

Sample crash report:
------------[ cut here ]------------
btrfs_abort_should_print_stack(__error)
WARNING: fs/btrfs/delayed-inode.c:1027 at __btrfs_update_delayed_inode+0xcb2/0xd60 fs/btrfs/delayed-inode.c:1027, CPU#0: kworker/u4:13/1063
Modules linked in:
CPU: 0 UID: 0 PID: 1063 Comm: kworker/u4:13 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_metadata_space
RIP: 0010:__btrfs_update_delayed_inode+0xcb2/0xd60 fs/btrfs/delayed-inode.c:1027
Code: 47 83 7c 24 18 fb 74 39 83 7c 24 18 f4 75 40 e8 04 47 94 fd eb 42 e8 fd 46 94 fd eb 10 e8 f6 46 94 fd eb 09 e8 ef 46 94 fd 90 <0f> 0b 90 44 89 e9 f7 d9 4c 8b 7c 24 28 4c 8b 74 24 30 e9 45 fd ff
RSP: 0018:ffffc90005237380 EFLAGS: 00010293
RAX: ffffffff84339a71 RBX: 00000000ffffffe4 RCX: ffff888036732580
RDX: 0000000000000000 RSI: ffffffff8f3ffc30 RDI: 00000000ffffffe4
RBP: ffffc900052374b0 R08: ffff888036732580 R09: 0000000000000003
R10: 00000000fffffffb R11: 0000000000000000 R12: dffffc0000000000
R13: 00000000ffffffe4 R14: ffff888052b168f0 R15: ffff8880427805a0
FS:  0000000000000000(0000) GS:ffff88808c2c6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a9a4c3c168 CR3: 00000000127c2000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1103 [inline]
 __btrfs_commit_inode_delayed_items+0x1d75/0x1ec0 fs/btrfs/delayed-inode.c:1127
 __btrfs_run_delayed_items+0x1d0/0x420 fs/btrfs/delayed-inode.c:1158
 flush_space+0x5fd/0xde0 fs/btrfs/space-info.c:875
 do_async_reclaim_metadata_space+0x3e8/0x940 fs/btrfs/space-info.c:1211
 btrfs_async_reclaim_metadata_space+0x89/0xe0 fs/btrfs/space-info.c:1278
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 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>

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/15 02:13 upstream 587858367581 81a27d1a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/09/13 15:01 upstream 2f0c1cf72f46 70a60e12 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/24 16:09 upstream 818bebeb63dd b55bd4c3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/24 16:09 upstream 818bebeb63dd b55bd4c3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/24 16:08 upstream 818bebeb63dd b55bd4c3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/24 16:07 upstream 818bebeb63dd b55bd4c3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/24 16:06 upstream 818bebeb63dd b55bd4c3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/24 16:06 upstream 818bebeb63dd b55bd4c3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/24 06:03 upstream 818bebeb63dd 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/21 18:31 upstream 818bebeb63dd 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/21 18:29 upstream 818bebeb63dd 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/20 23:33 upstream 9d2ed026f031 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/14 18:02 upstream 2f1baf1fc892 2cf1fbb7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/14 18:02 upstream 2f1baf1fc892 2cf1fbb7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/08/14 18:01 upstream 2f1baf1fc892 2cf1fbb7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
2026/06/26 06:32 upstream 4edcdefd4083 7ff32d8b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in __btrfs_update_delayed_inode
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.