syzbot


general protection fault in mntget

Status: premoderation: reported on 2026/04/26 03:42
Reported-by: syzbot+bbdfccb2daffd035d832@syzkaller.appspotmail.com
First crash: 84d, last: 10h58m
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 general protection fault in mntget 2 1 19d 19d 0/2 premoderation: reported on 2026/06/29 06:22
android-5-15 general protection fault in mntget 2 4 25d 81d 0/2 premoderation: reported on 2026/04/28 17:22
upstream KMSAN: uninit-value in enqueue_entity kernel 7 3 1613d 1655d 0/29 auto-closed as invalid on 2022/05/17 04:41

Sample crash report:
overlayfs: failed to create directory ./bus/work (errno: 22); mounting read-only
general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
CPU: 0 PID: 324 Comm: syz.0.8 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:mnt_add_count fs/namespace.c:157 [inline]
RIP: 0010:mntget+0x2e/0x60 fs/namespace.c:1227
Code: 41 56 53 48 89 fb e8 d1 1c b6 ff 48 85 db 74 30 e8 c7 1c b6 ff 4c 8d 73 48 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 c4 91 f0 ff 49 8b 06 65 ff 00 eb 05
RSP: 0018:ffffc90000d97660 EFLAGS: 00010206
RAX: 0000000000000009 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: ffffc900018ec000 RSI: 0000000000001abf RDI: 0000000000001ac0
RBP: ffffc90000d97670 R08: ffffc90000d9770f R09: 1ffff920001b2ee1
R10: dffffc0000000000 R11: fffff520001b2ee2 R12: 0000000000000000
R13: ffffc90000d97701 R14: 0000000000000049 R15: ffffc90000d97700
FS:  00007f4eeda7e6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555574f1f908 CR3: 000000011e0ad000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 path_get+0x37/0x80 fs/namei.c:486
 get_incfs_backing_path fs/incfs/data_mgmt.h:541 [inline]
 file_open+0x1e3/0x680 fs/incfs/vfs.c:1473
 do_dentry_open+0x7a5/0x10a0 fs/open.c:819
 open_with_fake_path+0x5a/0x90 fs/open.c:978
 ovl_open_realfile+0x161/0x1f0 fs/overlayfs/file.c:62
 ovl_open+0xdd/0x1f0 fs/overlayfs/file.c:158
 do_dentry_open+0x7a5/0x10a0 fs/open.c:819
 vfs_open+0x73/0x80 fs/open.c:944
 do_open fs/namei.c:3399 [inline]
 path_openat+0x26c3/0x3040 fs/namei.c:3517
 do_filp_open+0x1df/0x400 fs/namei.c:3544
 do_sys_openat2+0x19f/0x750 fs/open.c:1219
 do_sys_open fs/open.c:1235 [inline]
 __do_sys_openat fs/open.c:1251 [inline]
 __se_sys_openat fs/open.c:1246 [inline]
 __x64_sys_openat+0x136/0x160 fs/open.c:1246
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f4eef024e99
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:00007f4eeda7e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f4eef2acfa0 RCX: 00007f4eef024e99
RDX: 0000000000020040 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f4eef0baeaf R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001fe R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4eef2ad038 R14: 00007f4eef2acfa0 R15: 00007ffcc1947be8
Modules linked in:
---[ end trace 4459b7f0c0515108 ]---
RIP: 0010:mnt_add_count fs/namespace.c:157 [inline]
RIP: 0010:mntget+0x2e/0x60 fs/namespace.c:1227
Code: 41 56 53 48 89 fb e8 d1 1c b6 ff 48 85 db 74 30 e8 c7 1c b6 ff 4c 8d 73 48 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 c4 91 f0 ff 49 8b 06 65 ff 00 eb 05
RSP: 0018:ffffc90000d97660 EFLAGS: 00010206
RAX: 0000000000000009 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: ffffc900018ec000 RSI: 0000000000001abf RDI: 0000000000001ac0
RBP: ffffc90000d97670 R08: ffffc90000d9770f R09: 1ffff920001b2ee1
R10: dffffc0000000000 R11: fffff520001b2ee2 R12: 0000000000000000
R13: ffffc90000d97701 R14: 0000000000000049 R15: ffffc90000d97700
FS:  00007f4eeda7e6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e721ff8 CR3: 000000011e0ad000 CR4: 00000000003526b0
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 d1 1c b6 ff       	call   0xffb61cdc
   b:	48 85 db             	test   %rbx,%rbx
   e:	74 30                	je     0x40
  10:	e8 c7 1c b6 ff       	call   0xffb61cdc
  15:	4c 8d 73 48          	lea    0x48(%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 c4 91 f0 ff       	call   0xfff091fc
  38:	49 8b 06             	mov    (%r14),%rax
  3b:	65 ff 00             	incl   %gs:(%rax)
  3e:	eb 05                	jmp    0x45

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/18 17:33 android13-5.10-lts 50b3a256e550 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
2026/07/05 20:09 android13-5.10-lts 1bb06dbd8c78 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
2026/07/05 11:21 android13-5.10-lts 1bb06dbd8c78 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
2026/06/28 00:12 android13-5.10-lts 79e905dd56a7 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
2026/06/27 17:39 android13-5.10-lts 79e905dd56a7 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
2026/06/26 23:59 android13-5.10-lts 79e905dd56a7 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
2026/05/10 11:56 android13-5.10-lts 5feb5545d40a 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
2026/05/03 20:51 android13-5.10-lts 7ae299a5827a a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
2026/04/26 03:41 android13-5.10-lts d8c55bf860fd 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in mntget
* Struck through repros no longer work on HEAD.