syzbot


WARNING in filename_mkdirat

Status: upstream: reported syz repro on 2026/02/17 00:30
Subsystems: gfs2
[Documentation on labels]
Reported-by: syzbot+0ea5108a1f5fb4fcc2d8@syzkaller.appspotmail.com
First crash: 7d20h, last: 8h23m
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [gfs2?] WARNING in filename_mkdirat 3 (4) 2026/02/17 22:18

Sample crash report:
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff88804a18c9b8, owner = 0x0, curr 0xffff888000ec2480, list empty
WARNING: kernel/locking/rwsem.c:1381 at __up_write kernel/locking/rwsem.c:1380 [inline], CPU#0: syz.0.53/5774
WARNING: kernel/locking/rwsem.c:1381 at up_write+0x2d6/0x410 kernel/locking/rwsem.c:1643, CPU#0: syz.0.53/5774
Modules linked in:
CPU: 0 UID: 0 PID: 5774 Comm: syz.0.53 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_write kernel/locking/rwsem.c:1380 [inline]
RIP: 0010:up_write+0x388/0x410 kernel/locking/rwsem.c:1643
Code: cc 8b 49 c7 c2 c0 eb cc 8b 4c 0f 44 d0 48 8b 7c 24 08 48 c7 c6 20 ee cc 8b 48 8b 14 24 4c 89 f1 4d 89 e0 4c 8b 4c 24 10 41 52 <67> 48 0f b9 3a 48 83 c4 08 e8 ea 60 0a 03 e9 67 fd ff ff 48 c7 c1
RSP: 0000:ffffc90006407d80 EFLAGS: 00010246
RAX: ffffffff8bcceba0 RBX: ffff88804a18c9b8 RCX: ffff88804a18c9b8
RDX: 0000000000000000 RSI: ffffffff8bccee20 RDI: ffffffff9014bf50
RBP: ffff88804a18ca10 R08: 0000000000000000 R09: ffff888000ec2480
R10: ffffffff8bcceba0 R11: ffffed1009431939 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff88804a18c9b8 R15: 1ffff11009431938
FS:  00007f9e11bfe6c0(0000) GS:ffff88808ca62000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c000d54e20 CR3: 0000000041f2c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 inode_unlock include/linux/fs.h:1038 [inline]
 end_dirop fs/namei.c:2947 [inline]
 end_creating include/linux/namei.h:126 [inline]
 end_creating_path fs/namei.c:4962 [inline]
 filename_mkdirat+0x305/0x510 fs/namei.c:5271
 __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: 0033:0x7f9e10d9bf79
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:00007f9e11bfe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f9e11016090 RCX: 00007f9e10d9bf79
RDX: 00000000000001c0 RSI: 0000200000000140 RDI: ffffffffffffff9c
RBP: 00007f9e10e327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9e11016128 R14: 00007f9e11016090 R15: 00007ffffd54f8b8
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	49 c7 c2 c0 eb cc 8b 	mov    $0xffffffff8bccebc0,%r10
   7:	4c 0f 44 d0          	cmove  %rax,%r10
   b:	48 8b 7c 24 08       	mov    0x8(%rsp),%rdi
  10:	48 c7 c6 20 ee cc 8b 	mov    $0xffffffff8bccee20,%rsi
  17:	48 8b 14 24          	mov    (%rsp),%rdx
  1b:	4c 89 f1             	mov    %r14,%rcx
  1e:	4d 89 e0             	mov    %r12,%r8
  21:	4c 8b 4c 24 10       	mov    0x10(%rsp),%r9
  26:	41 52                	push   %r10
* 28:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2d:	48 83 c4 08          	add    $0x8,%rsp
  31:	e8 ea 60 0a 03       	call   0x30a6120
  36:	e9 67 fd ff ff       	jmp    0xfffffda2
  3b:	48                   	rex.W
  3c:	c7                   	.byte 0xc7
  3d:	c1                   	.byte 0xc1

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/17 00:29 upstream 0f2acd3148e0 5d52cba5 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-snapshot-upstream-root WARNING in filename_mkdirat
2026/02/11 18:51 upstream 192c0159402e 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in filename_mkdirat
2026/02/10 13:21 upstream 72c395024dac 91d776d3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in filename_mkdirat
2026/02/18 01:27 upstream d295082ea672 f4288eed .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_mkdirat
2026/02/16 07:46 upstream 26a4cfaff82a 1e62d198 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_mkdirat
2026/02/15 02:10 upstream 3e48a11675c5 1e62d198 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_mkdirat
2026/02/14 16:25 upstream 770aaedb461a 1e62d198 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_mkdirat
2026/02/13 20:54 upstream cee73b1e840c 1e62d198 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_mkdirat
2026/02/13 02:52 upstream 37a93dd5c49b 504cb1bf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_mkdirat
2026/02/11 14:05 upstream 192c0159402e 75707236 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_mkdirat
* Struck through repros no longer work on HEAD.