syzbot


WARNING in lookup_slow (4)

Status: moderation: reported on 2025/05/26 09:57
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+2b8d9d5c6bae92cffb1d@syzkaller.appspotmail.com
First crash: 301d, last: 27m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
d472dc8b-a44e-4060-ac78-4731914344d1 repro 💥 WARNING in lookup_slow (4) 2026/03/10 12:19 2026/03/10 12:19 2026/03/10 12:19 5c03941b7fba0fd3b0326afc981322c89fe9ba52+ failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 1
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in lookup_slow (2) -1 1 869d 869d 0/3 auto-obsoleted due to no activity on 2024/02/09 08:58
upstream WARNING in lookup_slow (2) fs -1 8 643d 675d 0/29 auto-obsoleted due to no activity on 2024/09/12 01:16
linux-6.6 WARNING in lookup_slow -1 1 71d 71d 0/2 upstream: reported on 2026/01/07 12:20
linux-6.1 WARNING in lookup_slow origin:upstream missing-backport -1 C inconclusive 9 218d 837d 0/3 upstream: reported C repro on 2023/12/02 22:03
upstream WARNING in lookup_slow (3) fs -1 1 451d 447d 0/29 auto-obsoleted due to no activity on 2025/02/21 12:31
linux-5.15 WARNING in lookup_slow (3) origin:lts-only -1 C error 8 8d15h 719d 0/3 upstream: reported C repro on 2024/03/30 12:27
upstream WARNING in lookup_slow ntfs3 -1 C error inconclusive 34 786d 1186d 0/29 auto-obsoleted due to no activity on 2024/05/02 19:30
linux-5.15 WARNING in lookup_slow -1 1 1029d 1029d 0/3 auto-obsoleted due to no activity on 2023/09/02 18:27

Sample crash report:
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem)): count = 0x0, magic = 0xffff8880465bc9b8, owner = 0x0, curr 0xffff88803aab24c0, list empty
WARNING: kernel/locking/rwsem.c:1354 at __up_read+0x532/0x6b0 kernel/locking/rwsem.c:1354, CPU#0: syz.0.0/5337
Modules linked in:
CPU: 0 UID: 0 PID: 5337 Comm: syz.0.0 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
RIP: 0010:__up_read+0x61a/0x6b0 kernel/locking/rwsem.c:1354
Code: ec cc 8b 49 c7 c2 a0 ec cc 8b 4c 0f 44 d0 48 8b 7c 24 28 48 c7 c6 40 ec cc 8b 48 89 da 48 8b 4c 24 20 4d 89 f0 4d 89 f9 41 52 <67> 48 0f b9 3a 48 83 c4 08 e8 f8 ff 0b 03 4c 8b 7c 24 18 e9 32 fb
RSP: 0018:ffffc9000e43f918 EFLAGS: 00010246
RAX: ffffffff8bccec80 RBX: 0000000000000000 RCX: ffff8880465bc9b8
RDX: 0000000000000000 RSI: ffffffff8bccec40 RDI: ffffffff90150e60
RBP: ffffc9000e43f9e8 R08: 0000000000000000 R09: ffff88803aab24c0
R10: ffffffff8bccec80 R11: ffffed1008cb7939 R12: ffff8880465bca10
R13: 1ffff92001c87f2c R14: 0000000000000000 R15: ffff88803aab24c0
FS:  00007f30ddbb36c0(0000) GS:ffff88808ca55000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000131f3000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 inode_unlock_shared include/linux/fs.h:1053 [inline]
 lookup_slow+0x5e/0x70 fs/namei.c:1934
 walk_component fs/namei.c:2279 [inline]
 link_path_walk+0xd1e/0x18d0 fs/namei.c:2647
 path_parentat fs/namei.c:2851 [inline]
 __filename_parentat+0x27f/0x6f0 fs/namei.c:2875
 filename_parentat fs/namei.c:2893 [inline]
 filename_create+0xd9/0x370 fs/namei.c:4903
 filename_mkdirat+0xd2/0x510 fs/namei.c:5259
 __do_sys_mkdirat fs/namei.c:5287 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5284
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f30e179c799
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:00007f30ddbb2fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f30e1a16180 RCX: 00007f30e179c799
RDX: 00000000000001c0 RSI: 0000200000000240 RDI: ffffffffffffff9c
RBP: 00007f30e1832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f30e1a16218 R14: 00007f30e1a16180 R15: 00007ffd62fe7148
 </TASK>
----------------
Code disassembly (best guess):
   0:	ec                   	in     (%dx),%al
   1:	cc                   	int3
   2:	8b 49 c7             	mov    -0x39(%rcx),%ecx
   5:	c2 a0 ec             	ret    $0xeca0
   8:	cc                   	int3
   9:	8b 4c 0f 44          	mov    0x44(%rdi,%rcx,1),%ecx
   d:	d0 48 8b             	rorb   $1,-0x75(%rax)
  10:	7c 24                	jl     0x36
  12:	28 48 c7             	sub    %cl,-0x39(%rax)
  15:	c6 40 ec cc          	movb   $0xcc,-0x14(%rax)
  19:	8b 48 89             	mov    -0x77(%rax),%ecx
  1c:	da 48 8b             	fimull -0x75(%rax)
  1f:	4c 24 20             	rex.WR and $0x20,%al
  22:	4d 89 f0             	mov    %r14,%r8
  25:	4d 89 f9             	mov    %r15,%r9
  28:	41 52                	push   %r10
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	48 83 c4 08          	add    $0x8,%rsp
  33:	e8 f8 ff 0b 03       	call   0x30c0030
  38:	4c 8b 7c 24 18       	mov    0x18(%rsp),%r15
  3d:	e9                   	.byte 0xe9
  3e:	32 fb                	xor    %bl,%bh

Crashes (19):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/19 21:15 upstream e9825d1c7957 0291cd06 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2026/03/12 16:11 upstream 80234b5ab240 4efadf07 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2026/03/12 09:22 upstream 80234b5ab240 2d88ab01 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2026/02/19 08:52 upstream 956b9cbd7f15 746545b8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2026/02/16 22:28 upstream 0f2acd3148e0 5d52cba5 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2026/01/16 01:43 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2026/01/14 17:04 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2026/01/12 05:41 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2026/01/06 00:06 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/12/05 11:58 upstream 2061f18ad76e d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/10/13 21:30 upstream 3a8660878839 b6605ba8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/09/08 17:33 upstream 76eeb9b8de98 d291dd2d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/08/10 12:23 upstream 561c80369df0 32a0e5ed .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/07/22 23:02 upstream 89be9a83ccf1 af30dea9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/07/11 14:08 upstream bc9ff192a6c9 3cda49cf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/06/25 14:44 upstream 7595b66ae9de 26d77996 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/06/19 09:02 upstream fb4d33ab452e ed3e87f7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/05/30 12:38 upstream f66bc387efbe 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
2025/05/22 09:52 upstream d608703fcdd9 0919b50b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in lookup_slow
* Struck through repros no longer work on HEAD.