syzbot


general protection fault in mntget

Status: premoderation: reported on 2026/04/28 17:22
Reported-by: syzbot+66d16afaffe626f8d3a6@syzkaller.appspotmail.com
First crash: 1d11h, last: 1d11h
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 general protection fault in mntget 2 1 4d01h 4d01h 0/2 premoderation: reported on 2026/04/26 03:42
upstream KMSAN: uninit-value in enqueue_entity kernel 7 3 1534d 1575d 0/29 auto-closed as invalid on 2022/05/17 04:41

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000000a: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000050-0x0000000000000057]
CPU: 1 PID: 901 Comm: syz.3.162 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:mnt_add_count fs/namespace.c:178 [inline]
RIP: 0010:mntget+0x2e/0x60 fs/namespace.c:1252
Code: 41 56 53 48 89 fb e8 a1 52 b1 ff 48 85 db 74 30 e8 97 52 b1 ff 4c 8d 73 50 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 f7 e8 04 86 f0 ff 49 8b 06 65 ff 00 eb 05
RSP: 0018:ffffc90000fc7620 EFLAGS: 00010206
RAX: 000000000000000a RBX: 0000000000000001 RCX: dffffc0000000000
RDX: ffffc90001f3e000 RSI: 00000000000009ce RDI: 00000000000009cf
RBP: ffffc90000fc7630 R08: ffffc90000fc76cf R09: 1ffff920001f8ed9
R10: dffffc0000000000 R11: fffff520001f8eda R12: 0000000000000000
R13: ffff8881136e2801 R14: 0000000000000051 R15: ffffc90000fc76c0
FS:  00007f1ebcfe16c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000004280 CR3: 0000000135182000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 path_get+0x37/0x80 fs/namei.c:546
 get_incfs_backing_path fs/incfs/data_mgmt.h:541 [inline]
 file_open+0x1e5/0x650 fs/incfs/vfs.c:1488
 do_dentry_open+0x834/0x1010 fs/open.c:828
 open_with_fake_path+0x5a/0x90 fs/open.c:994
 ovl_open_realfile+0x1bd/0x210 fs/overlayfs/file.c:63
 ovl_open+0xdd/0x1f0 fs/overlayfs/file.c:159
 do_dentry_open+0x834/0x1010 fs/open.c:828
 vfs_open+0x73/0x80 fs/open.c:960
 do_open fs/namei.c:3616 [inline]
 path_openat+0x26a6/0x2f20 fs/namei.c:3750
 do_filp_open+0x1e2/0x410 fs/namei.c:3777
 do_sys_openat2+0x15e/0x7f0 fs/open.c:1236
 do_sys_open fs/open.c:1252 [inline]
 __do_sys_openat fs/open.c:1268 [inline]
 __se_sys_openat fs/open.c:1263 [inline]
 __x64_sys_openat+0x136/0x160 fs/open.c:1263
 x64_sys_call+0x219/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:258
 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: 0033:0x7f1ebe586dd9
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:00007f1ebcfe1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f1ebe7fffa0 RCX: 00007f1ebe586dd9
RDX: 0000000000000000 RSI: 0000200000004280 RDI: ffffffffffffff9c
RBP: 00007f1ebe61cd69 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000002c R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1ebe800038 R14: 00007f1ebe7fffa0 R15: 00007ffec42226e8
 </TASK>
Modules linked in:
---[ end trace cd5c7d9317b1696f ]---
RIP: 0010:mnt_add_count fs/namespace.c:178 [inline]
RIP: 0010:mntget+0x2e/0x60 fs/namespace.c:1252
Code: 41 56 53 48 89 fb e8 a1 52 b1 ff 48 85 db 74 30 e8 97 52 b1 ff 4c 8d 73 50 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 f7 e8 04 86 f0 ff 49 8b 06 65 ff 00 eb 05
RSP: 0018:ffffc90000fc7620 EFLAGS: 00010206
RAX: 000000000000000a RBX: 0000000000000001 RCX: dffffc0000000000
RDX: ffffc90001f3e000 RSI: 00000000000009ce RDI: 00000000000009cf
RBP: ffffc90000fc7630 R08: ffffc90000fc76cf R09: 1ffff920001f8ed9
R10: dffffc0000000000 R11: fffff520001f8eda R12: 0000000000000000
R13: ffff8881136e2801 R14: 0000000000000051 R15: ffffc90000fc76c0
FS:  00007f1ebcfe16c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ebe5d44c0 CR3: 0000000135182000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	41 56                	push   %r14
   2:	53                   	push   %rbx
   3:	48 89 fb             	mov    %rdi,%rbx
   6:	e8 a1 52 b1 ff       	call   0xffb152ac
   b:	48 85 db             	test   %rbx,%rbx
   e:	74 30                	je     0x40
  10:	e8 97 52 b1 ff       	call   0xffb152ac
  15:	4c 8d 73 50          	lea    0x50(%rbx),%r14
  19:	4c 89 f0             	mov    %r14,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 f7             	mov    %r14,%rdi
  33:	e8 04 86 f0 ff       	call   0xfff0863c
  38:	49 8b 06             	mov    (%r14),%rax
  3b:	65 ff 00             	incl   %gs:(%rax)
  3e:	eb 05                	jmp    0x45

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/28 17:21 android13-5.15-lts e63ebedc51b2 ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in mntget
* Struck through repros no longer work on HEAD.