syzbot


WARNING in filename_symlinkat

Status: moderation: reported on 2026/02/14 15:13
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+5244f683c8b443a1fef6@syzkaller.appspotmail.com
First crash: 9d12h, last: 3d04h

Sample crash report:
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff888011b149b8, owner = 0x0, curr 0xffff888034934900, list empty
WARNING: kernel/locking/rwsem.c:1381 at __up_write kernel/locking/rwsem.c:1380 [inline], CPU#0: syz.0.0/5332
WARNING: kernel/locking/rwsem.c:1381 at up_write+0x2d6/0x410 kernel/locking/rwsem.c:1643, CPU#0: syz.0.0/5332
Modules linked in:
CPU: 0 UID: 0 PID: 5332 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_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: 0018:ffffc9000f0a7d80 EFLAGS: 00010246
RAX: ffffffff8bcceba0 RBX: ffff888011b149b8 RCX: ffff888011b149b8
RDX: 0000000000000000 RSI: ffffffff8bccee20 RDI: ffffffff9014bf50
RBP: ffff888011b14a10 R08: 0000000000000000 R09: ffff888034934900
R10: ffffffff8bcceba0 R11: ffffed1002362939 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888011b149b8 R15: 1ffff11002362938
FS:  00007f7c985d46c0(0000) GS:ffff88808ca62000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7c985d3ff8 CR3: 0000000041d99000 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_symlinkat+0x222/0x410 fs/namei.c:5642
 __do_sys_symlink fs/namei.c:5667 [inline]
 __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5663
 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: 0033:0x7f7c9c19bf79
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:00007f7c985d4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007f7c9c416180 RCX: 00007f7c9c19bf79
RDX: 0000000000000000 RSI: 00002000000004c0 RDI: 0000200000000380
RBP: 00007f7c9c2327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7c9c416218 R14: 00007f7c9c416180 R15: 00007ffe931d5768
 </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 (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/16 23:17 upstream 0f2acd3148e0 5d52cba5 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_symlinkat
2026/02/10 15:10 upstream 72c395024dac a076df6f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in filename_symlinkat
* Struck through repros no longer work on HEAD.