syzbot

general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047]
CPU: 0 PID: 360 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:d_really_is_positive include/linux/dcache.h:503 [inline]
RIP: 0010:fuse_atomic_open+0x2bb/0x2520 fs/fuse/dir.c:875
Code: 44 89 f0 83 e0 40 75 07 e8 62 fc 6f ff eb 34 4c 89 64 24 30 4d 8d 7c 24 30 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 a7 2a af ff 49 83 3f 00 74 57 e8 2c
RSP: 0018:ffffc90000ab7340 EFLAGS: 00010202
RAX: 0000000000000008 RBX: fffff52000156e80 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc90000ab7970 R08: ffff88810dd3e2c0 R09: fffff52000156ddc
R10: 00000000fffffffe R11: 0000000000000000 R12: 0000000000000010
R13: 0000000000000010 R14: 0000000000008241 R15: 0000000000000040
FS:  00007f596086f6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f596086eff8 CR3: 000000012e07c000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 atomic_open fs/namei.c:3333 [inline]
 lookup_open fs/namei.c:3441 [inline]
 open_last_lookups fs/namei.c:3540 [inline]
 path_openat+0xe31/0x2f20 fs/namei.c:3747
 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_creat fs/open.c:1328 [inline]
 __se_sys_creat fs/open.c:1322 [inline]
 __x64_sys_creat+0x8e/0xb0 fs/open.c:1322
 x64_sys_call+0x94a/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:86
 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: 0033:0x7f5960a2d799
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:00007f596086f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f5960ca7090 RCX: 00007f5960a2d799
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000180
RBP: 00007f5960ac3bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5960ca7128 R14: 00007f5960ca7090 R15: 00007ffe6d935658
 </TASK>
Modules linked in:
---[ end trace c411c6af5140d1ea ]---
RIP: 0010:d_really_is_positive include/linux/dcache.h:503 [inline]
RIP: 0010:fuse_atomic_open+0x2bb/0x2520 fs/fuse/dir.c:875
Code: 44 89 f0 83 e0 40 75 07 e8 62 fc 6f ff eb 34 4c 89 64 24 30 4d 8d 7c 24 30 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 a7 2a af ff 49 83 3f 00 74 57 e8 2c
RSP: 0018:ffffc90000ab7340 EFLAGS: 00010202
RAX: 0000000000000008 RBX: fffff52000156e80 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc90000ab7970 R08: ffff88810dd3e2c0 R09: fffff52000156ddc
R10: 00000000fffffffe R11: 0000000000000000 R12: 0000000000000010
R13: 0000000000000010 R14: 0000000000008241 R15: 0000000000000040
FS:  00007f596086f6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5960a7ae80 CR3: 000000012e07c000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	44 89 f0             	mov    %r14d,%eax
   3:	83 e0 40             	and    $0x40,%eax
   6:	75 07                	jne    0xf
   8:	e8 62 fc 6f ff       	call   0xff6ffc6f
   d:	eb 34                	jmp    0x43
   f:	4c 89 64 24 30       	mov    %r12,0x30(%rsp)
  14:	4d 8d 7c 24 30       	lea    0x30(%r12),%r15
  19:	4c 89 f8             	mov    %r15,%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 ff             	mov    %r15,%rdi
  33:	e8 a7 2a af ff       	call   0xffaf2adf
  38:	49 83 3f 00          	cmpq   $0x0,(%r15)
  3c:	74 57                	je     0x95
  3e:	e8                   	.byte 0xe8
  3f:	2c                   	.byte 0x2c