syzbot


general protection fault in ovl_lookup_single

Status: upstream: reported C repro on 2026/02/08 11:51
Reported-by: syzbot+26466157cdbd1e8c264b@syzkaller.appspotmail.com
First crash: 1d09h, last: 1d09h
Similar bugs (2)
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 763d 763d 0/2 auto-obsoleted due to no activity on 2024/04/07 02:55
android-6-12 general protection fault in ovl_lookup_single 2 C 5 3d15h 17d 0/1 premoderation: reported C repro on 2026/01/22 23:16

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 PID: 357 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:ovl_lookup_positive_unlocked fs/overlayfs/namei.c:203 [inline]
RIP: 0010:ovl_lookup_single+0x89/0x870 fs/overlayfs/namei.c:226
Code: 4d cf b3 ff 48 89 c3 48 3d 01 f0 ff ff 72 0a e8 ad cc 6e ff e9 de 03 00 00 49 89 dd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 44 05 00 84 c0 0f 85 ce 05 00 00 44 8b 23 44 89 e6 81 e6
RSP: 0018:ffffc90002d77a78 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000016 RCX: 32250c0bc0ebb700
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8881215c12a0
RBP: ffffc90002d77ab0 R08: ffff8881215c12a7 R09: 1ffff110242b8254
R10: dffffc0000000000 R11: ffffed10242b8255 R12: ffff88810d335000
R13: 0000000000000002 R14: 0000000000000000 R15: ffffffff853ba5a0
FS:  00007f868afb66c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f868af73ff8 CR3: 000000010f03a000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ovl_lookup_layer+0x355/0x420 fs/overlayfs/namei.c:310
 ovl_lookup+0x68d/0x1750 fs/overlayfs/namei.c:909
 __lookup_hash+0x114/0x250 fs/namei.c:1549
 filename_create+0x1d5/0x680 fs/namei.c:3616
 user_path_create fs/namei.c:3673 [inline]
 do_mkdirat+0x5e/0x340 fs/namei.c:3813
 __do_sys_mkdirat fs/namei.c:3831 [inline]
 __se_sys_mkdirat fs/namei.c:3829 [inline]
 __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f868b151eb9
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:00007f868afb6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f868b3ccfa0 RCX: 00007f868b151eb9
RDX: 0000000000000000 RSI: 0000200000002000 RDI: ffffffffffffff9c
RBP: 00007f868b1bfc1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f868b3cd038 R14: 00007f868b3ccfa0 R15: 00007ffebc42b4f8
Modules linked in:
---[ end trace 45e50b3c85edc398 ]---
RIP: 0010:ovl_lookup_positive_unlocked fs/overlayfs/namei.c:203 [inline]
RIP: 0010:ovl_lookup_single+0x89/0x870 fs/overlayfs/namei.c:226
Code: 4d cf b3 ff 48 89 c3 48 3d 01 f0 ff ff 72 0a e8 ad cc 6e ff e9 de 03 00 00 49 89 dd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 44 05 00 84 c0 0f 85 ce 05 00 00 44 8b 23 44 89 e6 81 e6
RSP: 0018:ffffc90002d77a78 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000016 RCX: 32250c0bc0ebb700
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8881215c12a0
RBP: ffffc90002d77ab0 R08: ffff8881215c12a7 R09: 1ffff110242b8254
R10: dffffc0000000000 R11: ffffed10242b8255 R12: ffff88810d335000
R13: 0000000000000002 R14: 0000000000000000 R15: ffffffff853ba5a0
FS:  00007f868afb66c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f868af73ff8 CR3: 000000010f03a000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	4d cf                	rex.WRB iretq
   2:	b3 ff                	mov    $0xff,%bl
   4:	48 89 c3             	mov    %rax,%rbx
   7:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax
   d:	72 0a                	jb     0x19
   f:	e8 ad cc 6e ff       	call   0xff6eccc1
  14:	e9 de 03 00 00       	jmp    0x3f7
  19:	49 89 dd             	mov    %rbx,%r13
  1c:	49 c1 ed 03          	shr    $0x3,%r13
  20:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  27:	fc ff df
* 2a:	41 0f b6 44 05 00    	movzbl 0x0(%r13,%rax,1),%eax <-- trapping instruction
  30:	84 c0                	test   %al,%al
  32:	0f 85 ce 05 00 00    	jne    0x606
  38:	44 8b 23             	mov    (%rbx),%r12d
  3b:	44 89 e6             	mov    %r12d,%esi
  3e:	81                   	.byte 0x81
  3f:	e6                   	.byte 0xe6

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/08 11:50 android13-5.10-lts 58c592510fcd 4c131dc4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in ovl_lookup_single
* Struck through repros no longer work on HEAD.