syzbot


general protection fault in ovl_lookup_single

Status: upstream: reported C repro on 2026/05/20 08:38
Reported-by: syzbot+d9d0ec2cc95b5f9a408e@syzkaller.appspotmail.com
First crash: 21h52m, last: 21h52m
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 general protection fault in ovl_lookup_single 2 C 1 27d 101d 0/2 upstream: reported C repro on 2026/02/08 11:51
android-6-1 general protection fault in ovl_lookup_single 2 1 864d 864d 0/2 auto-obsoleted due to no activity on 2024/04/07 02:55
android-6-12 general protection fault in ovl_lookup_single origin:downstream 2 C 5 33d 118d 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: 374 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:ovl_lookup_positive_unlocked fs/overlayfs/namei.c:207 [inline]
RIP: 0010:ovl_lookup_single+0x89/0x870 fs/overlayfs/namei.c:230
Code: bd 1d b2 ff 48 89 c3 48 3d 01 f0 ff ff 72 0a e8 dd 8e 68 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:ffffc90000b77a58 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000016 RCX: 8b5cd3dec39d5c00
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffffc90000b77a90 R08: ffff888111e0d2a7 R09: 1ffff110223c1a54
R10: dffffc0000000000 R11: ffffed10223c1a55 R12: ffff88810d1dd110
R13: 0000000000000002 R14: 0000000000000000 R15: ffffffff855e6e20
FS:  00007f26d58a76c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f26d5865d58 CR3: 000000012c4ba000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ovl_lookup_layer+0x355/0x420 fs/overlayfs/namei.c:314
 ovl_lookup+0x6aa/0x1750 fs/overlayfs/namei.c:914
 lookup_one_qstr_excl+0x114/0x250 fs/namei.c:1571
 filename_create+0x235/0x470 fs/namei.c:3844
 do_mkdirat+0x5c/0x4c0 fs/namei.c:4088
 __do_sys_mkdirat fs/namei.c:4113 [inline]
 __se_sys_mkdirat fs/namei.c:4111 [inline]
 __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4111
 x64_sys_call+0x37e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:259
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f26d5a44e59
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:00007f26d58a7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f26d5cbdfa0 RCX: 00007f26d5a44e59
RDX: 0000000000000000 RSI: 0000200000002000 RDI: ffffffffffffff9c
RBP: 00007f26d5adad6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f26d5cbe038 R14: 00007f26d5cbdfa0 R15: 00007ffd3e91c1f8
 </TASK>
Modules linked in:
---[ end trace e55cb5cbed593566 ]---
RIP: 0010:ovl_lookup_positive_unlocked fs/overlayfs/namei.c:207 [inline]
RIP: 0010:ovl_lookup_single+0x89/0x870 fs/overlayfs/namei.c:230
Code: bd 1d b2 ff 48 89 c3 48 3d 01 f0 ff ff 72 0a e8 dd 8e 68 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:ffffc90000b77a58 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000016 RCX: 8b5cd3dec39d5c00
RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff
RBP: ffffc90000b77a90 R08: ffff888111e0d2a7 R09: 1ffff110223c1a54
R10: dffffc0000000000 R11: ffffed10223c1a55 R12: ffff88810d1dd110
R13: 0000000000000002 R14: 0000000000000000 R15: ffffffff855e6e20
FS:  00007f26d58a76c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f26d5a92540 CR3: 000000012c4ba000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	bd 1d b2 ff 48       	mov    $0x48ffb21d,%ebp
   5:	89 c3                	mov    %eax,%ebx
   7:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax
   d:	72 0a                	jb     0x19
   f:	e8 dd 8e 68 ff       	call   0xff688ef1
  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
2026/05/20 08:37 android13-5.15-lts 05eea940894a 0909d65f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in ovl_lookup_single
* Struck through repros no longer work on HEAD.