syzbot

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 UID: 0 PID: 384 Comm: syz.2.17 Not tainted syzkaller #0 0016c7850c8f5e741b1ca5ad3edd21019ebf9493
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:d_really_is_positive include/linux/dcache.h:513 [inline]
RIP: 0010:fuse_atomic_open+0x1b6/0x440 fs/fuse/dir.c:962
Code: 8b 6d bc 44 89 ee 83 e6 40 31 ff e8 b4 6e 47 ff 44 89 e8 83 e0 40 75 07 e8 67 6a 47 ff eb 25 4d 8d 6e 30 4c 89 e8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ef e8 bc ee 9f ff 49 83 7d 00 00 74 26 e8
RSP: 0018:ffffc90000f1f970 EFLAGS: 00010206
RAX: 0000000000000006 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff8881135c3900 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc90000f1f9d0 R08: ffff8881135c3900 R09: 0000000000000000
R10: fffff520001e3ea0 R11: 0000000000000000 R12: ffff888115dc2000
R13: 0000000000000031 R14: 0000000000000001 R15: ffff88811ddc3600
FS:  00007efc23f0d6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efc23f0cff8 CR3: 000000010c3ea000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 atomic_open fs/namei.c:3463 [inline]
 lookup_open fs/namei.c:3574 [inline]
 open_last_lookups fs/namei.c:3702 [inline]
 path_openat+0x116c/0x34f0 fs/namei.c:3938
 do_filp_open+0x1f5/0x440 fs/namei.c:3968
 do_sys_openat2+0x134/0x1d0 fs/open.c:1440
 do_sys_open fs/open.c:1455 [inline]
 __do_sys_creat fs/open.c:1533 [inline]
 __se_sys_creat fs/open.c:1527 [inline]
 __x64_sys_creat+0x92/0xc0 fs/open.c:1527
 x64_sys_call+0x2710/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:86
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7efc22f9ce59
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:00007efc23f0d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007efc23216090 RCX: 00007efc22f9ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000180
RBP: 00007efc23032d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efc23216128 R14: 00007efc23216090 R15: 00007ffcbcfed918
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:d_really_is_positive include/linux/dcache.h:513 [inline]
RIP: 0010:fuse_atomic_open+0x1b6/0x440 fs/fuse/dir.c:962
Code: 8b 6d bc 44 89 ee 83 e6 40 31 ff e8 b4 6e 47 ff 44 89 e8 83 e0 40 75 07 e8 67 6a 47 ff eb 25 4d 8d 6e 30 4c 89 e8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ef e8 bc ee 9f ff 49 83 7d 00 00 74 26 e8
RSP: 0018:ffffc90000f1f970 EFLAGS: 00010206
RAX: 0000000000000006 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff8881135c3900 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc90000f1f9d0 R08: ffff8881135c3900 R09: 0000000000000000
R10: fffff520001e3ea0 R11: 0000000000000000 R12: ffff888115dc2000
R13: 0000000000000031 R14: 0000000000000001 R15: ffff88811ddc3600
FS:  00007efc23f0d6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efc23f0cff8 CR3: 000000010c3ea000 CR4: 00000000003526b0
----------------
Code disassembly (best guess):
   0:	8b 6d bc             	mov    -0x44(%rbp),%ebp
   3:	44 89 ee             	mov    %r13d,%esi
   6:	83 e6 40             	and    $0x40,%esi
   9:	31 ff                	xor    %edi,%edi
   b:	e8 b4 6e 47 ff       	call   0xff476ec4
  10:	44 89 e8             	mov    %r13d,%eax
  13:	83 e0 40             	and    $0x40,%eax
  16:	75 07                	jne    0x1f
  18:	e8 67 6a 47 ff       	call   0xff476a84
  1d:	eb 25                	jmp    0x44
  1f:	4d 8d 6e 30          	lea    0x30(%r14),%r13
  23:	4c 89 e8             	mov    %r13,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 ef             	mov    %r13,%rdi
  33:	e8 bc ee 9f ff       	call   0xff9feef4
  38:	49 83 7d 00 00       	cmpq   $0x0,0x0(%r13)
  3d:	74 26                	je     0x65
  3f:	e8                   	.byte 0xe8