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WARNING in btrfs_run_delayed_refs (2)

Status: upstream: reported C repro on 2023/06/22 14:13
Subsystems: btrfs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+810ea5febd3b79bdd384@syzkaller.appspotmail.com
First crash: 1070d, last: 19h44m
Cause bisection: introduced by (bisect log) :
commit f8f210dc84709804c9f952297f2bfafa6ea6b4bd
Author: Filipe Manana <fdmanana@suse.com>
Date: Tue Mar 21 11:13:59 2023 +0000

  btrfs: calculate the right space for delayed refs when updating global reserve

Crash: WARNING in __btrfs_free_extent (log)
Repro: C syz .config
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
455c35e0-8b5f-4313-9200-36cf78a87545 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in btrfs_run_delayed_refs (2) 2026/05/18 05:06 2026/05/18 05:06 2026/05/18 06:04 de5aae85e5f28e2fa1c7deefcc24fe286abe5140
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[syzbot] Monthly btrfs report (Mar 2026) 0 (1) 2026/03/03 08:06
[syzbot] Monthly btrfs report (Sep 2024) 0 (1) 2024/09/16 12:27
[syzbot] [btrfs?] WARNING in btrfs_run_delayed_refs (2) 0 (2) 2023/09/18 08:39
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 WARNING in btrfs_run_delayed_refs btrfs -1 C error 9 1179d 1559d 0/1 upstream: reported C repro on 2022/02/14 22:12
linux-6.1 WARNING in btrfs_run_delayed_refs -1 1 505d 505d 0/3 auto-obsoleted due to no activity on 2025/04/13 14:47
linux-6.1 WARNING in btrfs_run_delayed_refs (2) -1 1 366d 366d 0/3 auto-obsoleted due to no activity on 2025/08/31 03:17
upstream WARNING in btrfs_run_delayed_refs btrfs -1 C error done 15 1202d 1315d 22/29 fixed on 2023/03/15 11:57
linux-4.14 WARNING in btrfs_run_delayed_refs btrfs -1 C 1 1201d 1201d 0/1 upstream: reported C repro on 2023/02/08 10:50
linux-5.15 WARNING in btrfs_run_delayed_refs origin:lts-only -1 C error 25 18d 1147d 0/3 upstream: reported C repro on 2023/04/02 18:59
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2025/08/10 17:46 1h17m retest repro upstream OK log
2025/08/03 04:35 23m retest repro upstream OK log
2025/08/03 03:42 37m retest repro upstream OK log
2025/08/03 03:42 23m retest repro upstream OK log
2025/05/16 15:38 36m retest repro upstream report log
2025/05/16 15:38 16m retest repro upstream report log
2025/03/09 10:31 0m retest repro upstream error
2025/03/06 21:04 23m retest repro upstream report log
2025/03/06 21:04 27m retest repro upstream report log
2024/12/12 13:01 16m retest repro upstream report log
▶ ▼ Fix bisection attempts (12)
Created Duration User Patch Repo Result
2025/06/01 17:19 7m bisect fix upstream error job log
2025/03/24 04:37 1h50m bisect fix upstream OK (0) job log log
2024/12/29 06:25 2h12m bisect fix upstream OK (0) job log log
2024/11/14 06:24 4h56m bisect fix upstream OK (0) job log log
2024/10/08 11:00 2h02m bisect fix upstream OK (0) job log log
2024/09/07 08:37 1h54m bisect fix upstream OK (0) job log log
2024/08/08 05:23 3h13m bisect fix upstream OK (0) job log log
2024/07/08 18:57 2h46m bisect fix upstream OK (0) job log log
2023/12/03 17:17 1h49m bisect fix upstream OK (0) job log log
2023/11/01 12:10 4h11m bisect fix upstream OK (0) job log log
2023/10/01 23:16 2h17m bisect fix upstream OK (0) job log log
2023/07/27 09:39 2h14m bisect fix upstream OK (0) job log log
▶ ▼ Cause bisection attempts (2)
Created Duration User Patch Repo Result
2023/09/18 00:14 8h23m bisect upstream OK (1) job log log
2023/06/20 14:06 12h14m bisect upstream error job log
marked invalid by nogikh@google.com

Sample crash report:
BTRFS error (device loop2): failed to run delayed ref for logical 5402624 num_bytes 61440 type 178 action 1 ref_mod 1: -2
------------[ cut here ]------------
BTRFS: Transaction aborted (error -2)
WARNING: fs/btrfs/extent-tree.c:2247 at btrfs_run_delayed_refs+0x30b/0x3b0 fs/btrfs/extent-tree.c:2247, CPU#0: kworker/u8:4/59
Modules linked in:
CPU: 0 UID: 0 PID: 59 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events_unbound btrfs_async_reclaim_metadata_space
RIP: 0010:btrfs_run_delayed_refs+0x30e/0x3b0 fs/btrfs/extent-tree.c:2247
Code: 85 e4 75 07 e8 93 b3 e1 fd eb 7a e8 fc c0 c6 fd 84 c0 74 20 e8 83 b3 e1 fd eb 6a e8 7c b3 e1 fd 48 8d 3d 15 d6 36 0c 44 89 fe <67> 48 0f b9 3a e9 0b ff ff ff e8 93 bb cb 07 41 89 c4 31 ff 89 c6
RSP: 0018:ffffc9000211f7b8 EFLAGS: 00010293
RAX: ffffffff83e40c54 RBX: ffff8880786965c8 RCX: ffff88801cb81e80
RDX: 0000000000000000 RSI: 00000000fffffffe RDI: ffffffff901ae270
RBP: 0000000000000000 R08: ffff88801cb81e80 R09: 0000000000000003
R10: 00000000fffffffb R11: 0000000000000000 R12: ffff888031adc001
R13: ffff8880782bf000 R14: dffffc0000000000 R15: 00000000fffffffe
FS:  0000000000000000(0000) GS:ffff888125454000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005590ab78f950 CR3: 0000000032ef9000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 flush_space+0x28d/0xd80 fs/btrfs/space-info.c:-1
 do_async_reclaim_metadata_space+0x3fc/0x960 fs/btrfs/space-info.c:1187
 btrfs_async_reclaim_metadata_space+0x89/0xe0 fs/btrfs/space-info.c:1254
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 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:	85 e4                	test   %esp,%esp
   2:	75 07                	jne    0xb
   4:	e8 93 b3 e1 fd       	call   0xfde1b39c
   9:	eb 7a                	jmp    0x85
   b:	e8 fc c0 c6 fd       	call   0xfdc6c10c
  10:	84 c0                	test   %al,%al
  12:	74 20                	je     0x34
  14:	e8 83 b3 e1 fd       	call   0xfde1b39c
  19:	eb 6a                	jmp    0x85
  1b:	e8 7c b3 e1 fd       	call   0xfde1b39c
  20:	48 8d 3d 15 d6 36 0c 	lea    0xc36d615(%rip),%rdi        # 0xc36d63c
  27:	44 89 fe             	mov    %r15d,%esi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 0b ff ff ff       	jmp    0xffffff3f
  34:	e8 93 bb cb 07       	call   0x7cbbbcc
  39:	41 89 c4             	mov    %eax,%r12d
  3c:	31 ff                	xor    %edi,%edi
  3e:	89 c6                	mov    %eax,%esi

Crashes (185):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/08 17:12 upstream 3036cd0d3328 d9b7f621 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in btrfs_run_delayed_refs
2026/04/03 11:46 upstream d8a9a4b11a13 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in btrfs_run_delayed_refs
2026/02/11 13:27 upstream dc855b77719f 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in btrfs_run_delayed_refs
2024/05/12 03:20 upstream cf87f46fd34d 9026e142 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in btrfs_run_delayed_refs
2023/06/22 17:03 upstream dad9774deaf1 09ffe269 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-smack-root WARNING in btrfs_run_delayed_refs
2023/06/22 07:04 upstream dad9774deaf1 09ffe269 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-smack-root WARNING in btrfs_run_delayed_refs
2023/06/18 14:04 upstream 1b29d271614a f3921d4d .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-smack-root WARNING in btrfs_run_delayed_refs
2026/05/23 15:57 upstream 79bd2dded182 c69befb3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/23 05:31 upstream cca95436be15 c69befb3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/21 17:55 upstream 8bc67e4db64a 747d777d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/20 14:51 upstream 27fa82620cba 585486f8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/19 03:46 upstream 4d3a2a466b8d 9f74d399 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/17 16:45 upstream 6916d5703ddf de5aae85 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/17 05:19 upstream 6916d5703ddf de5aae85 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/16 12:45 upstream 6916d5703ddf a15a64a6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/15 03:29 upstream 66182ca873a4 6ccb967e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/14 12:35 upstream e1914add2799 6ccb967e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/11 11:37 upstream 5d6919055dec 845acb1c .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/10 21:06 upstream aa54b1d27fe0 29233ece .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/09 02:25 upstream cbf457c584b5 29233ece .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/08 18:54 upstream 917719c412c4 5633175a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/08 05:12 upstream fcee7d82f27d e358bca5 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/06 04:09 upstream 9207d47f966b 26da2c66 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/04 15:03 upstream 6d35786de281 85f1bcf2 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/04 06:05 upstream f377d0025eb0 a0d91488 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/04 04:17 upstream f377d0025eb0 a0d91488 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/04 00:31 upstream f377d0025eb0 a0d91488 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/03 13:34 upstream 66edb901bf87 a0d91488 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/02 01:24 upstream 6fe0be6dc7fa 753c55b9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/01 10:14 upstream 26fd6bff2c05 753c55b9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/05/01 01:16 upstream 08d0d3466664 a7464baf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/30 20:39 upstream 08d0d3466664 a7464baf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/30 13:13 upstream e75a43c7cec4 d926feac .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/29 20:54 upstream 57b8e2d666a3 7ca9e4d8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/29 08:13 upstream dca922e019dd 95008c03 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/28 07:33 upstream 3b3bea6d4b9c ce741359 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/27 19:53 upstream 254f49634ee1 0f700595 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/27 12:25 upstream 254f49634ee1 0f700595 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/27 07:01 upstream 14479877c1ec 9c2d0995 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/26 19:57 upstream 897d54018cc9 9c2d0995 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/26 10:58 upstream 897d54018cc9 9c2d0995 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/26 08:08 upstream 897d54018cc9 9c2d0995 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/26 04:55 upstream 897d54018cc9 9c2d0995 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/25 20:18 upstream 27d128c1cff6 9c2d0995 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/25 16:26 upstream 27d128c1cff6 9c2d0995 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/24 09:49 upstream dd6c438c3e64 9cfb3ca7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/24 05:38 upstream dd6c438c3e64 9cfb3ca7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/23 19:12 upstream 2e6803928193 629ff21a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/23 13:44 upstream 2a4c0c11c019 b10da5ec .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/22 13:12 upstream 6596a02b2078 0b6ab7ec .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/22 12:09 upstream 6596a02b2078 0b6ab7ec .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/21 13:09 upstream c1f49dea2b8f 3f2e655b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2026/04/21 04:48 upstream c1f49dea2b8f 3f2e655b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_run_delayed_refs
2024/05/12 03:19 upstream cf87f46fd34d 9026e142 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in btrfs_run_delayed_refs
2026/03/18 16:18 linux-next 8e5a478b6d6a 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in btrfs_run_delayed_refs
2024/04/30 19:47 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 6a71d2909427 9e0e6af1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in btrfs_run_delayed_refs
* Struck through repros no longer work on HEAD.