syzbot


WARNING in end_dirop

Status: upstream: reported on 2025/12/25 00:23
Subsystems: overlayfs
[Documentation on labels]
Reported-by: syzbot+19b2d871b77d222db434@syzkaller.appspotmail.com
First crash: 116d, last: 12h07m
Discussions (3)
Title Replies (including bot) Last reply
[syzbot] Monthly overlayfs report (Jan 2026) 0 (1) 2026/01/28 12:41
[syzbot] Monthly overlayfs report (Dec 2025) 0 (1) 2025/12/28 08:47
[syzbot] [overlayfs?] WARNING in end_dirop 0 (1) 2025/12/25 00:23

Sample crash report:
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff888058bc3ba0, owner = 0x0, curr 0xffff888037079ec0, list not empty
WARNING: kernel/locking/rwsem.c:1411 at __up_write kernel/locking/rwsem.c:1410 [inline], CPU#1: syz.5.6434/28844
WARNING: kernel/locking/rwsem.c:1411 at up_write+0x2d4/0x410 kernel/locking/rwsem.c:1682, CPU#1: syz.5.6434/28844
Modules linked in:
CPU: 1 UID: 0 PID: 28844 Comm: syz.5.6434 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:__up_write kernel/locking/rwsem.c:1410 [inline]
RIP: 0010:up_write+0x384/0x410 kernel/locking/rwsem.c:1682
Code: cc 8b 49 c7 c2 a0 f0 cc 8b 4c 0f 44 d0 48 8b 7c 24 08 48 c7 c6 40 f3 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 ae 50 0b 03 e9 6b fd ff ff 48 c7 c1
RSP: 0018:ffffc900064ef540 EFLAGS: 00010246
RAX: ffffffff8bccf0c0 RBX: ffff888058bc3ba0 RCX: ffff888058bc3ba0
RDX: 0000000000000000 RSI: ffffffff8bccf340 RDI: ffffffff903564b0
RBP: ffff888058bc3bf8 R08: 0000000000000000 R09: ffff888037079ec0
R10: ffffffff8bccf0c0 R11: ffffed100b178776 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888058bc3ba0 R15: 1ffff1100b178775
FS:  00007fdd22da26c0(0000) GS:ffff888125345000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8c3e233e9c CR3: 000000009461d000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 inode_unlock include/linux/fs.h:1039 [inline]
 end_dirop+0x7d/0x90 fs/namei.c:2951
 end_creating_keep include/linux/namei.h:144 [inline]
 ovl_workdir_create+0x51d/0x940 fs/overlayfs/super.c:346
 ovl_make_workdir fs/overlayfs/super.c:678 [inline]
 ovl_get_workdir fs/overlayfs/super.c:836 [inline]
 ovl_fill_super_creds fs/overlayfs/super.c:1449 [inline]
 ovl_fill_super+0x1a38/0x5e20 fs/overlayfs/super.c:1560
 vfs_get_super fs/super.c:1327 [inline]
 get_tree_nodev+0xbb/0x150 fs/super.c:1346
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3834
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4360
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdd21f9c819
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:00007fdd22da2028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fdd22216090 RCX: 00007fdd21f9c819
RDX: 0000200000000b80 RSI: 0000200000000240 RDI: 0000000000000000
RBP: 00007fdd22032c91 R08: 0000200000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdd22216128 R14: 00007fdd22216090 R15: 00007fff842ad978
 </TASK>
----------------
Code disassembly (best guess):
   0:	cc                   	int3
   1:	8b 49 c7             	mov    -0x39(%rcx),%ecx
   4:	c2 a0 f0             	ret    $0xf0a0
   7:	cc                   	int3
   8:	8b 4c 0f 44          	mov    0x44(%rdi,%rcx,1),%ecx
   c:	d0 48 8b             	rorb   $1,-0x75(%rax)
   f:	7c 24                	jl     0x35
  11:	08 48 c7             	or     %cl,-0x39(%rax)
  14:	c6 40 f3 cc          	movb   $0xcc,-0xd(%rax)
  18:	8b 48 8b             	mov    -0x75(%rax),%ecx
  1b:	14 24                	adc    $0x24,%al
  1d:	4c 89 f1             	mov    %r14,%rcx
  20:	4d 89 e0             	mov    %r12,%r8
  23:	4c 8b 4c 24 10       	mov    0x10(%rsp),%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 ae 50 0b 03       	call   0x30b50e6
  38:	e9 6b fd ff ff       	jmp    0xfffffda8
  3d:	48                   	rex.W
  3e:	c7                   	.byte 0xc7
  3f:	c1                   	.byte 0xc1

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/15 14:44 upstream 1f5ffc672165 c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in end_dirop
2026/03/04 22:08 upstream ecc64d2dc9ff e6b6b96b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in end_dirop
2026/02/26 14:11 upstream f4d0ec0aa20d ffa54287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in end_dirop
2026/01/20 02:27 upstream 24d479d26b25 572effc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in end_dirop
2026/01/07 13:07 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in end_dirop
2025/12/21 00:16 upstream d8ba32c5a460 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in end_dirop
2026/01/25 07:00 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 59e4d31a0470 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in end_dirop
* Struck through repros no longer work on HEAD.