syzbot


WARNING in ovl_create_real (3)

Status: upstream: reported on 2025/09/19 12:30
Subsystems: overlayfs
[Documentation on labels]
Reported-by: syzbot+59732cea2887c2408d94@syzkaller.appspotmail.com
First crash: 4d12h, last: 4d12h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [overlayfs?] WARNING in ovl_create_real (3) 0 (1) 2025/09/19 12:30
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in ovl_create_real (2) overlayfs -1 2 277d 280d 0/29 auto-obsoleted due to no activity on 2025/03/26 06:48
upstream WARNING in ovl_create_real overlayfs -1 C unreliable 164 1412d 1480d 20/29 fixed on 2022/03/08 16:11

Sample crash report:
overlayfs: ...falling back to redirect_dir=nofollow.
overlayfs: ...falling back to index=off.
overlayfs: ...falling back to uuid=null.
------------[ cut here ]------------
WARNING: CPU: 3 PID: 2192 at fs/overlayfs/dir.c:208 ovl_create_real+0x50f/0x780 fs/overlayfs/dir.c:208
Modules linked in:
CPU: 3 UID: 0 PID: 2192 Comm: syz.3.9488 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:ovl_create_real+0x50f/0x780 fs/overlayfs/dir.c:208
Code: 84 74 fc ff ff e8 b1 32 81 fe 48 63 ed e9 96 fc ff ff e8 a4 32 81 fe e9 2e fd ff ff 48 89 dd e9 84 fc ff ff e8 92 32 81 fe 90 <0f> 0b 90 e8 89 32 81 fe 48 89 ee 48 c7 c7 00 f0 ff ff e8 ea 2d 81
RSP: 0018:ffffc90007e9f4f0 EFLAGS: 00010283
RAX: 00000000000151fe RBX: ffff888038a89d60 RCX: ffffc9002b804000
RDX: 0000000000080000 RSI: ffffffff833a6aae RDI: ffff888038a89dc8
RBP: ffff888038a89d60 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880332f66a0
R13: ffff888031447c20 R14: 000000000000a000 R15: 000000000000a000
FS:  00007f83766e46c0(0000) GS:ffff8880d69b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ef21ff8 CR3: 0000000032996000 CR4: 0000000000352ef0
DR0: 0000000000000002 DR1: 0000000000000005 DR2: 8000000000000000
DR3: 1000000100000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ovl_create_temp+0x64/0xb0 fs/overlayfs/dir.c:229
 ovl_copy_up_workdir fs/overlayfs/copy_up.c:782 [inline]
 ovl_do_copy_up fs/overlayfs/copy_up.c:1001 [inline]
 ovl_copy_up_one+0xc18/0x38e0 fs/overlayfs/copy_up.c:1202
 ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1257
 ovl_rename+0x813/0x1710 fs/overlayfs/dir.c:1145
 vfs_rename+0xfba/0x22c0 fs/namei.c:5129
 do_renameat2+0x7f9/0xc50 fs/namei.c:5278
 __do_sys_renameat2 fs/namei.c:5312 [inline]
 __se_sys_renameat2 fs/namei.c:5309 [inline]
 __x64_sys_renameat2+0xe7/0x130 fs/namei.c:5309
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f837578eba9
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:00007f83766e4038 EFLAGS: 00000246 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007f83759d5fa0 RCX: 00007f837578eba9
RDX: ffffffffffffff9c RSI: 0000200000000180 RDI: ffffffffffffff9c
RBP: 00007f8375811e19 R08: 0000000000000002 R09: 0000000000000000
R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f83759d6038 R14: 00007f83759d5fa0 R15: 00007ffd8123fe08
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/15 12:20 upstream f83ec76bf285 e2beed91 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in ovl_create_real
* Struck through repros no longer work on HEAD.