syzbot


WARNING in do_mknodat (4)

Status: upstream: reported C repro on 2025/05/12 19:05
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+d5e7caced7e104629877@syzkaller.appspotmail.com
First crash: 76d, last: 5d23h
Bug presence (1)
Date Name Commit Repro Result
2025/07/23 upstream (ToT) 89be9a83ccf1 C [report] WARNING in do_mknodat
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in do_mknodat fs -1 1 948d 892d 0/29 closed as invalid on 2023/02/16 16:02
upstream WARNING in do_mknodat (3) fs -1 178 12d 513d 0/29 moderation: reported on 2024/03/01 11:23
linux-6.1 WARNING in do_mknodat -1 1 633d 633d 0/3 auto-obsoleted due to no activity on 2024/02/10 13:02
upstream WARNING in do_mknodat (2) fs -1 11 617d 886d 0/29 auto-obsoleted due to no activity on 2024/02/16 05:28
linux-6.1 WARNING in do_mknodat (2) -1 39 401d 468d 0/3 auto-obsoleted due to no activity on 2024/08/30 19:08
linux-5.15 WARNING in do_mknodat (3) -1 7 186d 283d 0/3 auto-obsoleted due to no activity on 2025/05/02 18:42
linux-6.1 WARNING in do_mknodat (3) -1 27 84d 294d 0/3 upstream: reported on 2024/10/06 10:51
linux-5.15 WARNING in do_mknodat (2) -1 4 422d 599d 0/3 auto-obsoleted due to no activity on 2024/09/08 20:03
linux-5.15 WARNING in do_mknodat -1 1 710d 710d 0/3 auto-obsoleted due to no activity on 2023/11/25 05:54

Sample crash report:
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff8880684a36d0, owner = 0x0, curr 0xffff888022d05940, list empty
WARNING: CPU: 0 PID: 4760 at kernel/locking/rwsem.c:1350 __up_write kernel/locking/rwsem.c:1349 [inline]
WARNING: CPU: 0 PID: 4760 at kernel/locking/rwsem.c:1350 up_write+0x3a1/0x420 kernel/locking/rwsem.c:1604
Modules linked in:
CPU: 0 PID: 4760 Comm: syz.4.183 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__up_write kernel/locking/rwsem.c:1349 [inline]
RIP: 0010:up_write+0x3a1/0x420 kernel/locking/rwsem.c:1604
Code: 44 d0 48 c7 c7 40 09 0b 8a 48 c7 c6 00 0c 0b 8a 48 8b 14 24 4c 89 f1 4d 89 e0 4c 8b 4c 24 08 41 52 e8 33 15 42 08 48 83 c4 08 <0f> 0b e9 6b fd ff ff 48 c7 c1 48 a2 69 8d 80 e1 07 80 c1 03 38 c1
RSP: 0018:ffffc9000504fdd0 EFLAGS: 00010292
RAX: 05f4beffd67f4900 RBX: ffff8880684a36d0 RCX: ffff888022d05940
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: dffffc0000000000 R09: ffffed10172067a8
R10: ffffed10172067a8 R11: 1ffff110172067a7 R12: 0000000000000000
R13: ffff8880684a3728 R14: ffff8880684a36d0 R15: 1ffff1100d0946db
FS:  00007ffbab77b6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000003a000 CR3: 00000000242e8000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 inode_unlock include/linux/fs.h:792 [inline]
 done_path_create fs/namei.c:3886 [inline]
 do_mknodat+0x408/0x620 fs/namei.c:4009
 __do_sys_mknod fs/namei.c:4027 [inline]
 __se_sys_mknod fs/namei.c:4025 [inline]
 __x64_sys_mknod+0x8a/0xa0 fs/namei.c:4025
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ffbac52c9a9
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:00007ffbab77b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000085
RAX: ffffffffffffffda RBX: 00007ffbac754080 RCX: 00007ffbac52c9a9
RDX: 0000000000000708 RSI: 0000000000000000 RDI: 000020000009e000
RBP: 00007ffbac5aed69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007ffbac754080 R15: 00007ffdbb3686b8
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/21 23:15 linux-5.15.y c79648372d02 56d87229 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan WARNING in do_mknodat
2025/07/21 17:34 linux-5.15.y c79648372d02 56d87229 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in do_mknodat
2025/07/21 17:29 linux-5.15.y c79648372d02 56d87229 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in do_mknodat
2025/06/20 15:11 linux-5.15.y 1c700860e8bc 804b3919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in do_mknodat
2025/05/26 06:31 linux-5.15.y 98f47d0e9b8c 2d4582d0 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan WARNING in do_mknodat
2025/05/12 19:04 linux-5.15.y 3b8db0e4f263 f6671af7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in do_mknodat
* Struck through repros no longer work on HEAD.