syzbot


general protection fault in mntget

Status: premoderation: reported on 2026/04/28 17:22
Reported-by: syzbot+66d16afaffe626f8d3a6@syzkaller.appspotmail.com
First crash: 57d, last: 2d00h
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 3 45d 60d 0/2 premoderation: reported on 2026/04/26 03:42
upstream KMSAN: uninit-value in enqueue_entity kernel 7 3 1590d 1631d 0/29 auto-closed as invalid on 2022/05/17 04:41

Sample crash report:
EXT4-fs (loop4): mounted filesystem without journal. Opts: nodelalloc,i_version,noblock_validity,noquota,data=ordered,max_batch_time=0x0000000000000000,abort,auto_da_alloc,lazytime,noauto_da_alloc,journal_dev=0x0000000000000003,,errors=continue. Quota mode: writeback.
incfs: ino conflict with backing FS 2
overlayfs: failed to create directory ./bus/work (errno: 22); mounting read-only
general protection fault, probably for non-canonical address 0xdffffc000000000a: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000050-0x0000000000000057]
CPU: 0 PID: 3272 Comm: syz.4.737 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:179 [inline]
RIP: 0010:mntget+0x2e/0x60 fs/namespace.c:1253
Code: 41 56 53 48 89 fb e8 21 1b b1 ff 48 85 db 74 30 e8 17 1b 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 c4 8b f0 ff 49 8b 06 65 ff 00 eb 05
RSP: 0018:ffffc90000a47640 EFLAGS: 00010206
RAX: 000000000000000a RBX: 0000000000000001 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffff8881097d61d0 RDI: 0000000000000001
RBP: ffffc90000a47650 R08: ffffc90000a476ef R09: 1ffff92000148edd
R10: dffffc0000000000 R11: fffff52000148ede R12: 0000000000000000
R13: ffffc90000a47601 R14: 0000000000000051 R15: ffffc90000a476e0
FS:  00007f0cdbb246c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff851fd7060 CR3: 000000011bf2e000 CR4: 00000000003526b0
DR0: 000000000000002a DR1: ffffffffff7fff00 DR2: 0000000080000001
DR3: 0000000000000005 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+0x1e3/0x680 fs/incfs/vfs.c:1488
 do_dentry_open+0x82a/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+0x82a/0x1010 fs/open.c:828
 vfs_open+0x73/0x80 fs/open.c:960
 do_open fs/namei.c:3616 [inline]
 path_openat+0x26e6/0x2f80 fs/namei.c:3750
 do_filp_open+0x1df/0x400 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: 0033:0x7f0cdd0c9e59
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:00007f0cdbb24028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0cdd342fa0 RCX: 00007f0cdd0c9e59
RDX: 0000000000000000 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f0cdd15fe6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0cdd343038 R14: 00007f0cdd342fa0 R15: 00007ffdc6be3408
 </TASK>
Modules linked in:
---[ end trace cc88619817e7de44 ]---
RIP: 0010:mnt_add_count fs/namespace.c:179 [inline]
RIP: 0010:mntget+0x2e/0x60 fs/namespace.c:1253
Code: 41 56 53 48 89 fb e8 21 1b b1 ff 48 85 db 74 30 e8 17 1b 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 c4 8b f0 ff 49 8b 06 65 ff 00 eb 05
RSP: 0018:ffffc90000a47640 EFLAGS: 00010206
RAX: 000000000000000a RBX: 0000000000000001 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffff8881097d61d0 RDI: 0000000000000001
RBP: ffffc90000a47650 R08: ffffc90000a476ef R09: 1ffff92000148edd
R10: dffffc0000000000 R11: fffff52000148ede R12: 0000000000000000
R13: ffffc90000a47601 R14: 0000000000000051 R15: ffffc90000a476e0
FS:  00007f0cdbb246c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f557cb5c000 CR3: 000000011bf2e000 CR4: 00000000003506a0
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 21 1b b1 ff       	call   0xffb11b2c
   b:	48 85 db             	test   %rbx,%rbx
   e:	74 30                	je     0x40
  10:	e8 17 1b b1 ff       	call   0xffb11b2c
  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 c4 8b f0 ff       	call   0xfff08bfc
  38:	49 8b 06             	mov    (%r14),%rax
  3b:	65 ff 00             	incl   %gs:(%rax)
  3e:	eb 05                	jmp    0x45

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/23 06:14 android13-5.15-lts 7ad09e849dbe 5a630be6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in mntget
2026/06/23 03:16 android13-5.15-lts 7ad09e849dbe 5a630be6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in mntget
2026/06/23 03:15 android13-5.15-lts 7ad09e849dbe 5a630be6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in mntget
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.