syzbot

general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
CPU: 1 PID: 374 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:d_really_is_positive include/linux/dcache.h:503 [inline]
RIP: 0010:fuse_atomic_open+0x238/0x2140 fs/fuse/dir.c:875
Code: 89 de 83 e6 40 31 ff e8 66 ea 71 ff 89 d8 83 e0 40 75 07 e8 aa e6 71 ff eb 2e 48 8b 44 24 58 48 8d 58 30 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 59 65 b0 ff 48 83 3b 00 0f 84 9c
RSP: 0018:ffffc9000403f380 EFLAGS: 00010206
RAX: 0000000000000009 RBX: 000000000000004a RCX: ffff888110692780
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc9000403f9b0 R08: ffff888110692780 R09: 0000000000000002
R10: 00000000fffffffe R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888110528800 R14: 1ffff92000807e88 R15: 000000000000001a
FS:  00007f7f4128d6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7f4128cf98 CR3: 0000000121e02000 CR4: 00000000003506a0
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+0xe31/0x2f10 fs/namei.c:3739
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3769
 do_sys_openat2+0x14c/0x7b0 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+0x136/0x160 fs/open.c:1261
 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: 0033:0x7f7f4143dec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7f4128d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f7f41695090 RCX: 00007f7f4143dec9
RDX: 0000000000000042 RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f7f414c0f91 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001ff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7f41695128 R14: 00007f7f41695090 R15: 00007ffe6748f7e8
 </TASK>
Modules linked in:
---[ end trace d8d5104f3a434b86 ]---
RIP: 0010:d_really_is_positive include/linux/dcache.h:503 [inline]
RIP: 0010:fuse_atomic_open+0x238/0x2140 fs/fuse/dir.c:875
Code: 89 de 83 e6 40 31 ff e8 66 ea 71 ff 89 d8 83 e0 40 75 07 e8 aa e6 71 ff eb 2e 48 8b 44 24 58 48 8d 58 30 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 59 65 b0 ff 48 83 3b 00 0f 84 9c
RSP: 0018:ffffc9000403f380 EFLAGS: 00010206
RAX: 0000000000000009 RBX: 000000000000004a RCX: ffff888110692780
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc9000403f9b0 R08: ffff888110692780 R09: 0000000000000002
R10: 00000000fffffffe R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888110528800 R14: 1ffff92000807e88 R15: 000000000000001a
FS:  00007f7f4128d6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7f4128cf98 CR3: 0000000121e02000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	89 de                	mov    %ebx,%esi
   2:	83 e6 40             	and    $0x40,%esi
   5:	31 ff                	xor    %edi,%edi
   7:	e8 66 ea 71 ff       	call   0xff71ea72
   c:	89 d8                	mov    %ebx,%eax
   e:	83 e0 40             	and    $0x40,%eax
  11:	75 07                	jne    0x1a
  13:	e8 aa e6 71 ff       	call   0xff71e6c2
  18:	eb 2e                	jmp    0x48
  1a:	48 8b 44 24 58       	mov    0x58(%rsp),%rax
  1f:	48 8d 58 30          	lea    0x30(%rax),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 59 65 b0 ff       	call   0xffb06592
  39:	48 83 3b 00          	cmpq   $0x0,(%rbx)
  3d:	0f                   	.byte 0xf
  3e:	84                   	.byte 0x84
  3f:	9c                   	pushf