syzbot

general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 PID: 298 Comm: syz-executor114 Not tainted 5.15.173-syzkaller-00206-gf7ce2ffd2f33 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:d_really_is_positive include/linux/dcache.h:503 [inline]
RIP: 0010:fuse_atomic_open+0x26f/0x3a90 fs/fuse/dir.c:875
Code: e0 40 4c 8b 64 24 48 75 07 e8 9d 48 66 ff eb 37 48 8b 44 24 70 48 8d 58 30 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 e3 9f a8 ff 48 83 3b 00 0f 84 a6 00
RSP: 0018:ffffc90000997280 EFLAGS: 00010207
RAX: 0000000000000006 RBX: 0000000000000035 RCX: dffffc0000000000
RDX: ffff88810c800000 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc900009978f0 R08: ffffffff820a22a2 R09: fffff52000132d99
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88812129c928
R13: ffff88810cb6e000 R14: 1ffff92000132e6c R15: 0000000000000005
FS:  00007f9752bb56c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002000b000 CR3: 0000000107fc7000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 atomic_open fs/namei.c:3325 [inline]
 lookup_open fs/namei.c:3433 [inline]
 open_last_lookups fs/namei.c:3532 [inline]
 path_openat+0xfde/0x2f40 fs/namei.c:3739
 do_filp_open+0x21c/0x460 fs/namei.c:3769
 do_sys_openat2+0x13f/0x820 fs/open.c:1234
 do_sys_open fs/open.c:1250 [inline]
 __do_sys_openat fs/open.c:1266 [inline]
 __se_sys_openat fs/open.c:1261 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1261
 x64_sys_call+0x6bf/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9752c177d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9752bb5218 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9752ca73d8 RCX: 00007f9752c177d9
RDX: 00000000000d0440 RSI: 0000000020000100 RDI: 00000000ffffff9c
RBP: 00007f9752ca73d0 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000017b R11: 0000000000000246 R12: 00007f9752c74114
R13: 000000000000006e R14: 00007f9752c72110 R15: 0030656c69662f2e
 </TASK>
Modules linked in:
---[ end trace 41a5871ed94e7448 ]---
RIP: 0010:d_really_is_positive include/linux/dcache.h:503 [inline]
RIP: 0010:fuse_atomic_open+0x26f/0x3a90 fs/fuse/dir.c:875
Code: e0 40 4c 8b 64 24 48 75 07 e8 9d 48 66 ff eb 37 48 8b 44 24 70 48 8d 58 30 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 e3 9f a8 ff 48 83 3b 00 0f 84 a6 00
RSP: 0018:ffffc90000997280 EFLAGS: 00010207
RAX: 0000000000000006 RBX: 0000000000000035 RCX: dffffc0000000000
RDX: ffff88810c800000 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc900009978f0 R08: ffffffff820a22a2 R09: fffff52000132d99
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88812129c928
R13: ffff88810cb6e000 R14: 1ffff92000132e6c R15: 0000000000000005
FS:  00007f9752bb56c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561386342148 CR3: 0000000107fc7000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	e0 40                	loopne 0x42
   2:	4c 8b 64 24 48       	mov    0x48(%rsp),%r12
   7:	75 07                	jne    0x10
   9:	e8 9d 48 66 ff       	call   0xff6648ab
   e:	eb 37                	jmp    0x47
  10:	48 8b 44 24 70       	mov    0x70(%rsp),%rax
  15:	48 8d 58 30          	lea    0x30(%rax),%rbx
  19:	48 89 d8             	mov    %rbx,%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:	48 89 df             	mov    %rbx,%rdi
  33:	e8 e3 9f a8 ff       	call   0xffa8a01b
  38:	48 83 3b 00          	cmpq   $0x0,(%rbx)
  3c:	0f                   	.byte 0xf
  3d:	84                   	.byte 0x84
  3e:	a6                   	cmpsb  %es:(%rdi),%ds:(%rsi)