WARNING in dlm_lowcomms_close

Status: upstream: reported C repro on 2026/07/31 17:14
Subsystems: gfs2
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+04dfbd15d442517e713a@syzkaller.appspotmail.com
First crash: 93d, last: 1h20m
Cause bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
fa86aee8 patching 💥 WARNING in dlm_lowcomms_close 2026/10/02 10:35 2026/10/02 10:35 2026/10/02 11:31 6d32eb1f
2e19a72d assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in dlm_lowcomms_close 2026/08/01 01:06 2026/08/01 01:06 2026/08/01 02:02 7664cf44
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] dlm: don't warn when closing a node without a connection 2 (2) 2026/10/14 11:49
[syzbot] [gfs2?] WARNING in dlm_lowcomms_close 0 (1) 2026/07/31 17:14
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 WARNING in dlm_lowcomms_close origin:upstream -1 syz, C 7 27d 75d 0/2 upstream: reported C repro on 2026/08/18 19:14

Sample crash report:
dlm: closing connection to node 1
------------[ cut here ]------------
!con
WARNING: fs/dlm/lowcomms.c:1455 at dlm_lowcomms_close+0x12d/0x470 fs/dlm/lowcomms.c:1455, CPU#1: syz-executor122/5598
Modules linked in:
CPU: 1 UID: 0 PID: 5598 Comm: syz-executor122 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:dlm_lowcomms_close+0x12d/0x470 fs/dlm/lowcomms.c:1455
Code: e9 57 9e 00 eb a6 44 89 e1 80 e1 07 80 c1 03 38 c1 7c ac 4c 89 e7 e8 62 06 0a 01 eb a2 e8 cb 57 9e 00 eb 05 e8 c4 57 9e 00 90 <0f> 0b 90 44 89 f7 e8 a8 54 4e 01 b8 fe ff ff ff 48 83 c4 20 5b 41
RSP: 0018:ffffc90004c67c40 EFLAGS: 00010293
RAX: ffffffff812821f5 RBX: 0000000000000001 RCX: ffff888037163e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000004 R09: ffffffff95caa980
R10: 00000000fe287748 R11: 00000000310b965c R12: 0000000000000000
R13: ffffffff81282128 R14: 0000000000000000 R15: 0000000000000000
FS:  000055556d267400(0000) GS:ffff888125cd5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ecf8794000 CR3: 0000000044882000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 drop_comm+0x61/0x190 fs/dlm/config.c:556
 client_drop_item fs/configfs/dir.c:970 [inline]
 configfs_rmdir+0x85f/0x950 fs/configfs/dir.c:1567
 vfs_rmdir+0x3e9/0x6b0 fs/namei.c:5515
 filename_rmdir+0x292/0x520 fs/namei.c:5572
 __do_sys_unlinkat fs/namei.c:5747 [inline]
 __se_sys_unlinkat+0x71/0x1a0 fs/namei.c:5740
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc0ae124589
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff08de5668 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00002000000001c0 RCX: 00007fc0ae124589
RDX: 0000000000000200 RSI: 00002000000001c0 RDI: 00000000ffffff9c
RBP: 0000000000000001 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000006 R11: 0000000000000246 R12: 00007fff08de57d8
R13: 431bde82d7b634db R14: 00007fc0ae1b7c40 R15: 0000000000000002
 </TASK>

Crashes (433):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/02 22:00 upstream 89a312991dc6 85995287 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in dlm_lowcomms_close
2026/08/11 19:21 upstream f5bbbfec59b4 71790083 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in dlm_lowcomms_close
2026/09/05 18:07 upstream 4d7d9486c04d 4f7b22a0 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in dlm_lowcomms_close
2026/07/31 06:40 upstream 3708dd948844 aaffb173 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in dlm_lowcomms_close
2026/07/31 05:59 upstream 3708dd948844 aaffb173 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in dlm_lowcomms_close
2026/07/31 05:28 upstream 3708dd948844 aaffb173 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in dlm_lowcomms_close
2026/07/31 04:48 upstream 3708dd948844 aaffb173 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in dlm_lowcomms_close
2026/10/22 21:46 linux-next bd1ecbb61afe 4ba27f85 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in dlm_lowcomms_close
2026/09/22 20:11 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 38872197cae2 3e2106e5 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in dlm_lowcomms_close
2026/08/21 18:38 upstream 818bebeb63dd 1e72964b .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in dlm_lowcomms_close
2026/10/27 18:12 upstream d135ab453a74 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in dlm_lowcomms_close
2026/09/10 00:57 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in dlm_lowcomms_close
2026/09/09 15:05 upstream 893e11787f78 8387c273 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in dlm_lowcomms_close
2026/09/03 15:36 upstream 940de590b839 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in dlm_lowcomms_close
2026/09/01 19:23 upstream 786262be6048 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in dlm_lowcomms_close
2026/11/01 22:56 upstream 46fec1c3029b 25a0ae84 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/11/01 10:45 upstream cbbddb6b08cc 25a0ae84 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/31 10:34 upstream abf8c33470f7 2041d3f8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/30 18:35 upstream d89e1d186ec9 0ec395f8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/30 16:06 upstream d89e1d186ec9 0ec395f8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/30 07:17 upstream 4dd16e31135e b498adee .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/30 02:23 upstream 4dd16e31135e b498adee .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/29 07:21 upstream c339f4010dea b1d00f76 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/29 05:24 upstream c339f4010dea b1d00f76 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/28 18:11 upstream 65ba8f34ec88 858db2ec .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/28 16:26 upstream 65ba8f34ec88 858db2ec .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/28 06:32 upstream 62c457528529 96923c60 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/25 09:17 upstream 330517c63aa9 1d9ca40b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/24 12:24 upstream 26344c0dd32a 1d9ca40b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/24 11:19 upstream 26344c0dd32a 1d9ca40b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/23 03:11 upstream a1c2b1da93f5 d566bfda .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/22 08:40 upstream 4df4d2a577db 4ba27f85 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/22 07:08 upstream 4df4d2a577db 4ba27f85 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/21 19:48 upstream a804c5742bff 42e06812 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/21 18:22 upstream a804c5742bff 42e06812 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/20 16:11 upstream f47d223627f8 df8746fb .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/20 03:49 upstream c03c1a14507d 21286ae2 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/19 17:04 upstream c03c1a14507d 440f8011 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/18 18:18 upstream 32c52ec87d62 432c0077 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/18 15:11 upstream 32c52ec87d62 432c0077 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/18 00:15 upstream 58161ead29e5 432c0077 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/17 22:28 upstream 58161ead29e5 432c0077 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/17 19:00 upstream 58161ead29e5 432c0077 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/17 04:58 upstream 70dd4ee72eb2 432c0077 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/16 14:36 upstream 2f2f7eeef8b0 b1757810 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/16 03:58 upstream 045958acaa75 3f2522c6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/16 02:07 upstream 045958acaa75 3f2522c6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/14 15:56 upstream 4056b3c9d3c9 1a71827b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/13 03:10 upstream 24a19b953e2a 745a967f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/11 14:28 upstream a5ebb76233b7 4f92358f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/11 11:01 upstream a5ebb76233b7 4f92358f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/11 04:23 upstream a5ebb76233b7 4f92358f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/09 09:27 upstream 6c377d19d4a5 b2734a59 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/08 23:33 upstream 0c2669a9f4a1 9d4697fa .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/08 09:36 upstream 7b63ef2d55f2 4f6a9fcf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/08 03:36 upstream 7b63ef2d55f2 4f6a9fcf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/07 16:25 upstream 602042bf29f6 6520ecdb .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/06 11:43 upstream 2c3418fffa9d f7710056 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/10/06 05:38 upstream 2c3418fffa9d f7710056 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in dlm_lowcomms_close
2026/09/07 21:07 upstream df2908090cda 5e4626f5 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in dlm_lowcomms_close
2026/09/05 08:31 upstream 654ae5d73c05 4f7b22a0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in dlm_lowcomms_close
2026/09/03 16:02 linux-next 32b6ef9a5d0e 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in dlm_lowcomms_close
2026/09/06 03:12 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 73ae59e97596 4f7b22a0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in dlm_lowcomms_close
2026/08/19 23:48 git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git for-next 8da45c93dfa9 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-riscv64 WARNING in dlm_lowcomms_close
2026/08/18 09:28 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master ff68e5f557f6 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in dlm_lowcomms_close
* Struck through repros no longer work on HEAD.