syzbot


general protection fault in ovl_lookup_single

Status: premoderation: reported C repro on 2026/01/22 23:16
Bug presence: origin:downstream
[Documentation on labels]
Reported-by: syzbot+41ffa60446c91f25279f@syzkaller.appspotmail.com
First crash: 3d03h, last: 2d22h
Bug presence (3)
Date Name Commit Repro Result
2026/01/23 android16-6.12 (ToT) b9bf9f78c6bb C [report] general protection fault in ovl_lookup_single
2026/01/23 lts (merge base) 318a47068f7b C Didn't crash
2026/01/23 upstream (ToT) a66191c590b3 C Failed due to an error; will retry later
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 general protection fault in ovl_lookup_single 2 1 748d 748d 0/2 auto-obsoleted due to no activity on 2024/04/07 02:55

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 UID: 0 PID: 383 Comm: syz.2.17 Not tainted syzkaller #0 ad62f380a7f2f1545e15d1dbb2af73c398067985
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:ovl_lookup_positive_unlocked fs/overlayfs/namei.c:213 [inline]
RIP: 0010:ovl_lookup_single+0x209/0xb90 fs/overlayfs/namei.c:240
Code: 4d cf a5 ff 48 89 c3 48 3d 01 f0 ff ff 72 0a e8 2d 24 40 ff e9 9a 04 00 00 49 89 dc 49 c1 ec 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 04 04 84 c0 0f 85 58 07 00 00 44 8b 33 44 89 f6 81 e6 00
RSP: 0018:ffffc9000116f900 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000016 RCX: f7cf6f5a8d314f00
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff888121e1b698
RBP: ffffc9000116f9f0 R08: ffff888121e1b69f R09: 1ffff110243c36d3
R10: dffffc0000000000 R11: ffffed10243c36d4 R12: 0000000000000002
R13: 1ffff9200022df2c R14: ffff88811543c578 R15: ffff888112855be8
FS:  00007f5ee2cbf6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ee2c7dd58 CR3: 000000012acd0000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 ovl_lookup_layer+0x355/0x420 fs/overlayfs/namei.c:333
 ovl_lookup+0x8d2/0x1d60 fs/overlayfs/namei.c:1124
 lookup_one_qstr_excl+0x12c/0x280 fs/namei.c:1641
 filename_create+0x239/0x480 fs/namei.c:4035
 do_mkdirat+0xa9/0x530 fs/namei.c:4280
 __do_sys_mkdirat fs/namei.c:4303 [inline]
 __se_sys_mkdirat fs/namei.c:4301 [inline]
 __x64_sys_mkdirat+0x8b/0xa0 fs/namei.c:4301
 x64_sys_call+0x2ba8/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:259
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f5ee1d9acb9
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:00007f5ee2cbf028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f5ee2015fa0 RCX: 00007f5ee1d9acb9
RDX: 0000000000000000 RSI: 0000200000002000 RDI: ffffffffffffff9c
RBP: 00007f5ee1e08bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5ee2016038 R14: 00007f5ee2015fa0 R15: 00007fff1ace0ad8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ovl_lookup_positive_unlocked fs/overlayfs/namei.c:213 [inline]
RIP: 0010:ovl_lookup_single+0x209/0xb90 fs/overlayfs/namei.c:240
Code: 4d cf a5 ff 48 89 c3 48 3d 01 f0 ff ff 72 0a e8 2d 24 40 ff e9 9a 04 00 00 49 89 dc 49 c1 ec 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 04 04 84 c0 0f 85 58 07 00 00 44 8b 33 44 89 f6 81 e6 00
RSP: 0018:ffffc9000116f900 EFLAGS: 00010203

RAX: dffffc0000000000 RBX: 0000000000000016 RCX: f7cf6f5a8d314f00
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff888121e1b698
RBP: ffffc9000116f9f0 R08: ffff888121e1b69f R09: 1ffff110243c36d3
R10: dffffc0000000000 R11: ffffed10243c36d4 R12: 0000000000000002
R13: 1ffff9200022df2c R14: ffff88811543c578 R15: ffff888112855be8
FS:  00007f5ee2cbf6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ee2c7dd58 CR3: 000000012acd0000 CR4: 00000000003526b0
----------------
Code disassembly (best guess):
   0:	4d cf                	rex.WRB iretq
   2:	a5                   	movsl  %ds:(%rsi),%es:(%rdi)
   3:	ff 48 89             	decl   -0x77(%rax)
   6:	c3                   	ret
   7:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax
   d:	72 0a                	jb     0x19
   f:	e8 2d 24 40 ff       	call   0xff402441
  14:	e9 9a 04 00 00       	jmp    0x4b3
  19:	49 89 dc             	mov    %rbx,%r12
  1c:	49 c1 ec 03          	shr    $0x3,%r12
  20:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  27:	fc ff df
* 2a:	41 0f b6 04 04       	movzbl (%r12,%rax,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 58 07 00 00    	jne    0x78f
  37:	44 8b 33             	mov    (%rbx),%r14d
  3a:	44 89 f6             	mov    %r14d,%esi
  3d:	81                   	.byte 0x81
  3e:	e6 00                	out    %al,$0x0

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/23 03:29 android16-6.12 da606bc67c00 82c9c083 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in ovl_lookup_single
2026/01/23 02:28 android16-6.12 da606bc67c00 82c9c083 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in ovl_lookup_single
2026/01/23 01:29 android16-6.12 da606bc67c00 82c9c083 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in ovl_lookup_single
2026/01/23 00:22 android16-6.12 da606bc67c00 82c9c083 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in ovl_lookup_single
2026/01/22 23:15 android16-6.12 da606bc67c00 82c9c083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in ovl_lookup_single
* Struck through repros no longer work on HEAD.