WARNING in do_new_mount (6)

Status: moderation: reported on 2026/02/18 14:16
Subsystems: fs
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+aa9301d3b66961eb2421@syzkaller.appspotmail.com
First crash: 198d, last: 15h35m
✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision
faead6e8 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in do_new_mount (6) 2026/05/31 16:09 2026/05/31 16:09 2026/05/31 17:18 6b4a8443
0dd1d590 assessment-security 💥 WARNING in do_new_mount (6) 2026/05/15 05:28 2026/05/15 05:28 2026/05/15 05:30 6ccb967e
58385d5e repro WARNING in do_new_mount (6) 2026/03/07 03:20 2026/03/07 03:20 2026/03/07 03:29 31e9c887
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in do_new_mount -1 2 1106d 1123d 0/3 auto-obsoleted due to no activity on 2023/11/29 20:19
linux-6.1 WARNING in do_new_mount (2) -1 1 269d 269d 0/3 auto-obsoleted due to no activity on 2026/03/15 04:54
upstream WARNING in do_new_mount fs -1 4 1118d 1137d 0/29 auto-obsoleted due to no activity on 2023/11/07 02:18
upstream WARNING in do_new_mount (5) fs -1 1 441d 437d 0/29 auto-obsoleted due to no activity on 2025/09/14 00:27
upstream WARNING in do_new_mount (3) fs -1 1 606d 602d 0/29 auto-obsoleted due to no activity on 2025/03/03 15:54
linux-6.1 WARNING in do_new_mount -1 4 776d 879d 0/3 auto-obsoleted due to no activity on 2024/10/24 11:22
upstream WARNING in do_new_mount (2) fs -1 22 722d 876d 0/29 auto-obsoleted due to no activity on 2024/12/07 21:46
upstream WARNING in do_new_mount (4) fs -1 2 534d 535d 0/29 auto-obsoleted due to no activity on 2025/06/13 20:52

Sample crash report:
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current)
WARNING: kernel/locking/rtmutex_common.h:193 at debug_rt_mutex_unlock kernel/locking/rtmutex_common.h:193 [inline], CPU#1: syz.6.506/11073
WARNING: kernel/locking/rtmutex_common.h:193 at rt_mutex_slowunlock+0x734/0xa30 kernel/locking/rtmutex.c:1432, CPU#1: syz.6.506/11073
Modules linked in:
CPU: 1 UID: 0 PID: 11073 Comm: syz.6.506 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:debug_rt_mutex_unlock kernel/locking/rtmutex_common.h:193 [inline]
RIP: 0010:rt_mutex_slowunlock+0x73b/0xa30 kernel/locking/rtmutex.c:1432
Code: b1 8f 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 cf 02 00 00 83 3d 39 ec 5a 04 00 75 13 48 8d 3d 4c de 5d 04 48 c7 c6 20 28 6d 8b <67> 48 0f b9 3a 90 e9 cf f9 ff ff 48 8d 3d 43 de 5d 04 67 48 0f b9
RSP: 0000:ffffc900060b7bc0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff88805bc43948 RCX: 0000000000080000
RDX: ffffc9001fdcb000 RSI: ffffffff8b6d2820 RDI: ffffffff8fb4e0e0
RBP: ffffc900060b7cb0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f63dd9 R12: dffffc0000000000
R13: 1ffff92000c16f80 R14: ffff88805bc438f8 R15: 0000000000000246
FS:  00007f9f618c56c0(0000) GS:ffff888125cd6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0819bf8c50 CR3: 0000000058bdc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 inode_unlock include/linux/fs.h:1034 [inline]
 __unlock_mount fs/namespace.c:2808 [inline]
 unlock_mount fs/namespace.c:2818 [inline]
 do_new_mount_fc fs/namespace.c:3795 [inline]
 do_new_mount+0x82d/0xdc0 fs/namespace.c:3848
 do_mount fs/namespace.c:4181 [inline]
 __do_sys_mount fs/namespace.c:4397 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4374
 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: 0033:0x7f9f6368e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9f618c5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9f63916090 RCX: 00007f9f6368e159
RDX: 0000200000000100 RSI: 00002000000000c0 RDI: 0000000000000000
RBP: 00007f9f63725024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9f63916128 R14: 00007f9f63916090 R15: 00007ffd34d8f868
 </TASK>
----------------
Code disassembly (best guess):
   0:	b1 8f                	mov    $0x8f,%cl
   2:	48 c1 e8 03          	shr    $0x3,%rax
   6:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax
   b:	84 c0                	test   %al,%al
   d:	0f 85 cf 02 00 00    	jne    0x2e2
  13:	83 3d 39 ec 5a 04 00 	cmpl   $0x0,0x45aec39(%rip)        # 0x45aec53
  1a:	75 13                	jne    0x2f
  1c:	48 8d 3d 4c de 5d 04 	lea    0x45dde4c(%rip),%rdi        # 0x45dde6f
  23:	48 c7 c6 20 28 6d 8b 	mov    $0xffffffff8b6d2820,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	90                   	nop
  30:	e9 cf f9 ff ff       	jmp    0xfffffa04
  35:	48 8d 3d 43 de 5d 04 	lea    0x45dde43(%rip),%rdi        # 0x45dde7f
  3c:	67                   	addr32
  3d:	48                   	rex.W
  3e:	0f                   	.byte 0xf
  3f:	b9                   	.byte 0xb9

Crashes (39):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/31 06:59 upstream a23cbb05744b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/30 15:24 upstream 08dbfad3f504 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/30 12:53 upstream 08dbfad3f504 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/30 07:57 upstream 08dbfad3f504 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/29 05:32 upstream c20313e98b04 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/26 08:18 upstream 45c13f3f9e3b 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/22 02:58 upstream 818bebeb63dd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/21 01:49 upstream 9328b3b03bdc 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/19 23:27 upstream bd5f485f3f02 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in do_new_mount
2026/08/19 15:36 upstream bd5f485f3f02 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/17 15:13 upstream 8d3ae59288f1 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/16 14:05 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/15 22:05 upstream 15ef2f78c49d 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/13 20:54 upstream 3aa1dcaa4f6f b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/12 11:13 upstream f5bbbfec59b4 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/10 22:55 upstream d58772d8520c 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/03 15:08 upstream 075b74841bd0 6b7c9f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/02 09:26 upstream 2d2338c93da7 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/07/30 04:04 upstream fc46aed51f62 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/07/25 10:55 upstream e2a936998ab2 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/07/24 18:31 upstream 48a5a7ab8d6a dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/07/20 02:12 upstream 82a47586c0b9 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/07/17 07:57 upstream fce2dfa773ce 7f27c57a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/06/02 06:36 upstream 6f3ed7fec72f 1095583b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/05/14 09:06 upstream e1914add2799 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/04/29 05:45 upstream dca922e019dd 95008c03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/04/22 16:18 upstream 6596a02b2078 4595e353 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/03/07 13:07 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/02/20 08:09 upstream 8bf22c33e7a1 17d780d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/02/14 14:05 upstream c22e26bd0906 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/08/29 08:21 upstream cf72cbb39da8 2f52988a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
2026/08/26 16:43 upstream 818bebeb63dd a2b77b9e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
2026/08/20 09:54 upstream a4ff2be345d0 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
2026/08/18 01:20 upstream ff68e5f557f6 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
2026/08/17 11:50 upstream 8d3ae59288f1 905244d6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
2026/08/13 17:45 upstream 3d6d817622b0 4d118901 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
2026/08/09 02:03 upstream a59f57e2aa12 5d63f80b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
2026/08/02 01:27 upstream 02dc699f83d0 e611ffe1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
2026/02/25 16:13 upstream 7dff99b35460 c162cde9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
* Struck through repros no longer work on HEAD.