overlayfs: workdir and upperdir must reside under the same mount
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: 1653 Comm: syz.3.367 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:d_really_is_positive include/linux/dcache.h:499 [inline]
RIP: 0010:fuse_atomic_open+0x2c8/0x2250 fs/fuse/dir.c:853
Code: 75 ff 44 89 f0 83 e0 40 4c 8b 74 24 10 75 07 e8 ee e5 75 ff eb 32 4c 89 3c 24 48 8b 44 24 40 4c 8d 78 30 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 69 63 b0 ff 49 83 3f 00 74 5b e8
RSP: 0018:ffffc900013c7380 EFLAGS: 00010206
RAX: 0000000000000009 RBX: fffff52000278e84 RCX: 0000000000000002
RDX: ffff8881168d3b40 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc900013c7990 R08: ffff8881168d3b40 R09: fffff52000278de4
R10: 00000000fffffffe R11: 0000000000000002 R12: ffff88810baf1000
R13: dffffc0000000000 R14: ffff88812c62a880 R15: 000000000000004b
FS:  00007f7927f6b6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1978e50d58 CR3: 000000012e983000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 atomic_open fs/namei.c:3122 [inline]
 lookup_open fs/namei.c:3227 [inline]
 open_last_lookups fs/namei.c:3325 [inline]
 path_openat+0xf99/0x31c0 fs/namei.c:3514
 do_filp_open+0x1e2/0x410 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: 0033:0x7f792950eeb9
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:00007f7927f6b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f7929789fa0 RCX: 00007f792950eeb9
RDX: 0000000000000040 RSI: 0000200000000400 RDI: ffffffffffffff9c
RBP: 00007f792957cc1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000083 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f792978a038 R14: 00007f7929789fa0 R15: 00007ffd4ea6eca8
Modules linked in:
---[ end trace fe957b4a7d4fc507 ]---
RIP: 0010:d_really_is_positive include/linux/dcache.h:499 [inline]
RIP: 0010:fuse_atomic_open+0x2c8/0x2250 fs/fuse/dir.c:853
Code: 75 ff 44 89 f0 83 e0 40 4c 8b 74 24 10 75 07 e8 ee e5 75 ff eb 32 4c 89 3c 24 48 8b 44 24 40 4c 8d 78 30 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 69 63 b0 ff 49 83 3f 00 74 5b e8
RSP: 0018:ffffc900013c7380 EFLAGS: 00010206
RAX: 0000000000000009 RBX: fffff52000278e84 RCX: 0000000000000002
RDX: ffff8881168d3b40 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc900013c7990 R08: ffff8881168d3b40 R09: fffff52000278de4
R10: 00000000fffffffe R11: 0000000000000002 R12: ffff88810baf1000
R13: dffffc0000000000 R14: ffff88812c62a880 R15: 000000000000004b
FS:  00007f7927f6b6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555576224948 CR3: 000000012e983000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	75 ff                	jne    0x1
   2:	44 89 f0             	mov    %r14d,%eax
   5:	83 e0 40             	and    $0x40,%eax
   8:	4c 8b 74 24 10       	mov    0x10(%rsp),%r14
   d:	75 07                	jne    0x16
   f:	e8 ee e5 75 ff       	call   0xff75e602
  14:	eb 32                	jmp    0x48
  16:	4c 89 3c 24          	mov    %r15,(%rsp)
  1a:	48 8b 44 24 40       	mov    0x40(%rsp),%rax
  1f:	4c 8d 78 30          	lea    0x30(%rax),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ff             	mov    %r15,%rdi
  34:	e8 69 63 b0 ff       	call   0xffb063a2
  39:	49 83 3f 00          	cmpq   $0x0,(%r15)
  3d:	74 5b                	je     0x9a
  3f:	e8                   	.byte 0xe8