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: 375 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:493 [inline]
RIP: 0010:fuse_atomic_open+0x174/0x3c0 fs/fuse/dir.c:901
Code: 8b 6d c4 44 89 ee 83 e6 40 31 ff e8 06 3a 66 ff 44 89 e8 83 e0 40 75 07 e8 d9 35 66 ff eb 26 4d 8d 6e 30 4c 89 e8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ef e8 3d 68 ab ff 49 83 7d 00 00 74 21
RSP: 0018:ffffc900036a78f8 EFLAGS: 00010203
RAX: 0000000000000008 RBX: ffff888112816800 RCX: 0000000000000000
RDX: ffff888113b5bcc0 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc900036a7950 R08: ffff888113b5bcc0 R09: fffff520006d4e94
R10: 00000000fffffffe R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000047 R14: 0000000000000017 R15: ffff8881246daa80
FS:  00007f2e82f726c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2e82f71ff8 CR3: 000000012d5ce000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 atomic_open fs/namei.c:3352 [inline]
 lookup_open fs/namei.c:3460 [inline]
 open_last_lookups fs/namei.c:3557 [inline]
 path_openat+0xe57/0x2f80 fs/namei.c:3787
 do_filp_open+0x1f1/0x430 fs/namei.c:3817
 do_sys_openat2+0x15e/0x810 fs/open.c:1343
 do_sys_open fs/open.c:1359 [inline]
 __do_sys_creat fs/open.c:1437 [inline]
 __se_sys_creat fs/open.c:1431 [inline]
 __x64_sys_creat+0x8e/0xb0 fs/open.c:1431
 x64_sys_call+0x116/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:86
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2e8219c629
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:00007f2e82f72028 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f2e82416090 RCX: 00007f2e8219c629
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000180
RBP: 00007f2e82232b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2e82416128 R14: 00007f2e82416090 R15: 00007ffe4d2e91f8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:d_really_is_positive include/linux/dcache.h:493 [inline]
RIP: 0010:fuse_atomic_open+0x174/0x3c0 fs/fuse/dir.c:901
Code: 8b 6d c4 44 89 ee 83 e6 40 31 ff e8 06 3a 66 ff 44 89 e8 83 e0 40 75 07 e8 d9 35 66 ff eb 26 4d 8d 6e 30 4c 89 e8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ef e8 3d 68 ab ff 49 83 7d 00 00 74 21
RSP: 0018:ffffc900036a78f8 EFLAGS: 00010203
RAX: 0000000000000008 RBX: ffff888112816800 RCX: 0000000000000000
RDX: ffff888113b5bcc0 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc900036a7950 R08: ffff888113b5bcc0 R09: fffff520006d4e94
R10: 00000000fffffffe R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000047 R14: 0000000000000017 R15: ffff8881246daa80
FS:  00007f2e82f726c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ee5b0729f0 CR3: 000000012d5ce000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	8b 6d c4             	mov    -0x3c(%rbp),%ebp
   3:	44 89 ee             	mov    %r13d,%esi
   6:	83 e6 40             	and    $0x40,%esi
   9:	31 ff                	xor    %edi,%edi
   b:	e8 06 3a 66 ff       	call   0xff663a16
  10:	44 89 e8             	mov    %r13d,%eax
  13:	83 e0 40             	and    $0x40,%eax
  16:	75 07                	jne    0x1f
  18:	e8 d9 35 66 ff       	call   0xff6635f6
  1d:	eb 26                	jmp    0x45
  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:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ef             	mov    %r13,%rdi
  34:	e8 3d 68 ab ff       	call   0xffab6876
  39:	49 83 7d 00 00       	cmpq   $0x0,0x0(%r13)
  3e:	74 21                	je     0x61