syzbot


WARNING in end_dirop

Status: upstream: reported on 2025/12/25 00:23
Subsystems: overlayfs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+19b2d871b77d222db434@syzkaller.appspotmail.com
First crash: 212d, last: 23h00m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
949d729d-fe0b-4dbe-a485-2bd64d0b69bb assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in end_dirop 2026/05/23 18:52 2026/05/23 18:52 2026/05/23 19:54 c69befb30ac10e158cc9d1557b508ee3f0eca1de

			
		
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:
loop7: detected capacity change from 0 to 4096
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff88804f666c18, owner = 0x0, curr 0xffff8880302d8000, list not empty
WARNING: kernel/locking/rwsem.c:1413 at __up_write kernel/locking/rwsem.c:1412 [inline], CPU#1: syz.7.1819/10957
WARNING: kernel/locking/rwsem.c:1413 at up_write+0x35c/0x4a0 kernel/locking/rwsem.c:1688, CPU#1: syz.7.1819/10957
Modules linked in:
CPU: 1 UID: 0 PID: 10957 Comm: syz.7.1819 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
RIP: 0010:__up_write kernel/locking/rwsem.c:1412 [inline]
RIP: 0010:up_write+0x40f/0x4a0 kernel/locking/rwsem.c:1688
Code: ed 8b 49 c7 c2 40 03 ed 8b 4c 0f 44 d0 48 8b 7c 24 10 48 c7 c6 e0 05 ed 8b 48 8b 14 24 48 8b 4c 24 08 4d 89 e0 4d 89 f9 41 52 <67> 48 0f b9 3a 48 83 c4 08 e8 03 e8 2d 03 e9 d6 fc ff ff 48 c7 c1
RSP: 0018:ffffc900044b7540 EFLAGS: 00010246
RAX: ffffffff8bed0360 RBX: ffff88804f666c18 RCX: ffff88804f666c18
RDX: 0000000000000000 RSI: ffffffff8bed05e0 RDI: ffffffff905b0e70
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffff8880302d8000
R10: ffffffff8bed0360 R11: ffffed1009eccd85 R12: 0000000000000000
R13: ffff88804f666c20 R14: ffff88804f666c70 R15: ffff8880302d8000
FS:  00007f9c91da06c0(0000) GS:ffff888125054000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000420000 CR3: 00000000521b2000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 inode_unlock include/linux/fs.h:1034 [inline]
 end_dirop+0x7d/0x90 fs/namei.c:2955
 end_creating_keep include/linux/namei.h:138 [inline]
 ovl_workdir_create+0x4a5/0x8b0 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+0x19ad/0x5d40 fs/overlayfs/super.c:1560
 vfs_get_super fs/super.c:1267 [inline]
 get_tree_nodev+0xbb/0x150 fs/super.c:1286
 vfs_get_tree+0x92/0x2a0 fs/super.c:1694
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount+0x319/0xdc0 fs/namespace.c:3841
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4367
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9c90f9de99
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:00007f9c91da0028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9c91225fa0 RCX: 00007f9c90f9de99
RDX: 0000200000000b80 RSI: 0000200000000100 RDI: 0000000000000000
RBP: 00007f9c91033eaf R08: 0000200000000040 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9c91226038 R14: 00007f9c91225fa0 R15: 00007ffe0477e1d8
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	49 c7 c2 40 03 ed 8b 	mov    $0xffffffff8bed0340,%r10
   7:	4c 0f 44 d0          	cmove  %rax,%r10
   b:	48 8b 7c 24 10       	mov    0x10(%rsp),%rdi
  10:	48 c7 c6 e0 05 ed 8b 	mov    $0xffffffff8bed05e0,%rsi
  17:	48 8b 14 24          	mov    (%rsp),%rdx
  1b:	48 8b 4c 24 08       	mov    0x8(%rsp),%rcx
  20:	4d 89 e0             	mov    %r12,%r8
  23:	4d 89 f9             	mov    %r15,%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 03 e8 2d 03       	call   0x32de839
  36:	e9 d6 fc ff ff       	jmp    0xfffffd11
  3b:	48                   	rex.W
  3c:	c7                   	.byte 0xc7
  3d:	c1                   	.byte 0xc1

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/21 00:14 upstream b95f03f04d47 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in end_dirop
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.