syzbot

general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
CPU: 0 PID: 377 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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 a6 44 68 ff 44 89 e8 83 e0 40 75 07 e8 79 40 68 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 ad af ac ff 49 83 7d 00 00 74 21
RSP: 0018:ffffc90000ad7938 EFLAGS: 00010206
RAX: 0000000000000009 RBX: ffff888113f3a800 RCX: 0000000000000000
RDX: ffff88812d733cc0 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc90000ad7990 R08: ffff88812d733cc0 R09: 0000000000000002
R10: 00000000fffffffe R11: 0000000000000000 R12: dffffc0000000000
R13: 000000000000004a R14: 000000000000001a R15: ffff88812314c440
FS:  00007f92789e36c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 00000001213c0000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 atomic_open fs/namei.c:3344 [inline]
 lookup_open fs/namei.c:3452 [inline]
 open_last_lookups fs/namei.c:3549 [inline]
 path_openat+0xe44/0x2f50 fs/namei.c:3779
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3809
 do_sys_openat2+0x185/0x7e0 fs/open.c:1341
 do_sys_open fs/open.c:1357 [inline]
 __do_sys_openat fs/open.c:1373 [inline]
 __se_sys_openat fs/open.c:1368 [inline]
 __x64_sys_openat+0x136/0x160 fs/open.c:1368
 x64_sys_call+0x783/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9277b8efc9
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:00007f92789e3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9277de6090 RCX: 00007f9277b8efc9
RDX: 0000000000000042 RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f9277c11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001ff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9277de6128 R14: 00007f9277de6090 R15: 00007ffcba45ee28
 </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 a6 44 68 ff 44 89 e8 83 e0 40 75 07 e8 79 40 68 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 ad af ac ff 49 83 7d 00 00 74 21
RSP: 0018:ffffc90000ad7938 EFLAGS: 00010206
RAX: 0000000000000009 RBX: ffff888113f3a800 RCX: 0000000000000000
RDX: ffff88812d733cc0 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc90000ad7990 R08: ffff88812d733cc0 R09: 0000000000000002
R10: 00000000fffffffe R11: 0000000000000000 R12: dffffc0000000000
R13: 000000000000004a R14: 000000000000001a R15: ffff88812314c440
FS:  00007f92789e36c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000b000 CR3: 00000001213c0000 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 a6 44 68 ff       	call   0xff6844b6
  10:	44 89 e8             	mov    %r13d,%eax
  13:	83 e0 40             	and    $0x40,%eax
  16:	75 07                	jne    0x1f
  18:	e8 79 40 68 ff       	call   0xff684096
  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 ad af ac ff       	call   0xffacafe6
  39:	49 83 7d 00 00       	cmpq   $0x0,0x0(%r13)
  3e:	74 21                	je     0x61