syzbot


WARNING in lookup_slow

Status: upstream: reported on 2026/01/07 12:20
Reported-by: syzbot+46b2450852b8be2d7e30@syzkaller.appspotmail.com
First crash: 8d18h, last: 8d18h
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 806d 806d 0/3 auto-obsoleted due to no activity on 2024/02/09 08:58
upstream WARNING in lookup_slow (2) fs -1 8 581d 612d 0/29 auto-obsoleted due to no activity on 2024/09/12 01:16
linux-6.1 WARNING in lookup_slow origin:upstream missing-backport -1 C inconclusive 9 155d 775d 0/3 upstream: reported C repro on 2023/12/02 22:03
upstream WARNING in lookup_slow (3) fs -1 1 388d 384d 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 16d 656d 0/3 upstream: reported C repro on 2024/03/30 12:27
upstream WARNING in lookup_slow (4) fs -1 14 5h04m 234d 0/29 moderation: reported on 2025/05/26 09:57
upstream WARNING in lookup_slow ntfs3 -1 C error inconclusive 34 723d 1123d 0/29 auto-obsoleted due to no activity on 2024/05/02 19:30
linux-5.15 WARNING in lookup_slow -1 1 966d 966d 0/3 auto-obsoleted due to no activity on 2023/09/02 18:27

Sample crash report:
DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem)): count = 0x0, magic = 0xffff8880575c79e0, owner = 0x0, curr 0xffff88802cc1bc00, list empty
WARNING: CPU: 1 PID: 13081 at kernel/locking/rwsem.c:1343 __up_read+0x5e5/0x670 kernel/locking/rwsem.c:1343
Modules linked in:
CPU: 1 PID: 13081 Comm: syz.0.943 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__up_read+0x5e5/0x670 kernel/locking/rwsem.c:1343
Code: 0f 44 d0 48 c7 c7 80 b0 aa 8a 48 c7 c6 20 b1 aa 8a 4c 89 ea 48 8b 4c 24 08 4d 89 e0 4d 89 f1 41 52 e8 7f a4 e9 ff 48 83 c4 08 <0f> 0b e9 85 fb ff ff 48 c7 c1 f0 55 4a 8e 80 e1 07 80 c1 03 38 c1
RSP: 0018:ffffc90004897a60 EFLAGS: 00010296
RAX: 2798dd4473166a00 RBX: ffff8880575c79e0 RCX: 0000000000080000
RDX: ffffc90014bb3000 RSI: 000000000000e7b7 RDI: 000000000000e7b8
RBP: ffffc90004897b20 R08: ffffc90004897667 R09: 1ffff92000912ecc
R10: dffffc0000000000 R11: fffff52000912ecd R12: 0000000000000000
R13: 0000000000000000 R14: ffff88802cc1bc00 R15: ffff8880575c7a38
FS:  00007fcb1e3d56c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fefc41d4f98 CR3: 000000007b0e6000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 inode_unlock_shared include/linux/fs.h:819 [inline]
 lookup_slow+0x5e/0x70 fs/namei.c:1720
 walk_component+0x2be/0x3f0 fs/namei.c:2010
 lookup_last fs/namei.c:2467 [inline]
 path_lookupat+0x169/0x440 fs/namei.c:2491
 filename_lookup+0x1f4/0x510 fs/namei.c:2520
 user_path_at_empty+0x42/0x60 fs/namei.c:2917
 user_path_at include/linux/namei.h:57 [inline]
 do_mount fs/namespace.c:3723 [inline]
 __do_sys_mount fs/namespace.c:3935 [inline]
 __se_sys_mount+0x29b/0x3c0 fs/namespace.c:3912
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcb2018f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcb1e3d5038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fcb203e6180 RCX: 00007fcb2018f749
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000200000000440
RBP: 00007fcb20213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000003ab1019 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb203e6218 R14: 00007fcb203e6180 R15: 00007fff6e4adcb8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/07 12:19 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in lookup_slow
* Struck through repros no longer work on HEAD.