syzbot

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 UID: 0 PID: 297 Comm: syz-executor182 Not tainted 6.12.30-syzkaller-g379b99745e88 #0 11522de10711ed1cb6b8bd0366ad005e7892f9f5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:traverse_mounts fs/namei.c:1459 [inline]
RIP: 0010:handle_mounts fs/namei.c:1571 [inline]
RIP: 0010:step_into+0x121/0xf50 fs/namei.c:1891
Code: 74 24 08 c6 44 24 7f 00 43 0f b6 04 3c 84 c0 4d 89 fd 0f 85 10 0c 00 00 45 8b 36 4c 8b bc 24 a8 00 00 00 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 0f 0c 00 00 45 8b 3f 44 89 fe 81 e6 00
RSP: 0018:ffffc900012afa80 EFLAGS: 00010207
RAX: 0000000000000003 RBX: ffffc900012afcc0 RCX: ffff88812e1c9300
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900012afb98 R08: ffff88813401129f R09: 1ffff11026802253
R10: dffffc0000000000 R11: ffffed1026802254 R12: 1ffff92000255f9f
R13: dffffc0000000000 R14: 0000000000000000 R15: 000000000000001d
FS:  00007fdebf4ec6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055da7b71b388 CR3: 0000000101f0e000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 walk_component+0x255/0x440 fs/namei.c:2059
 lookup_last fs/namei.c:2556 [inline]
 path_lookupat+0x180/0x4a0 fs/namei.c:2580
 filename_lookup+0x1f5/0x520 fs/namei.c:2609
 do_linkat+0xcd/0x470 fs/namei.c:4789
 __do_sys_link fs/namei.c:4843 [inline]
 __se_sys_link fs/namei.c:4841 [inline]
 __x64_sys_link+0x86/0xa0 fs/namei.c:4841
 x64_sys_call+0x1cf5/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:87
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fdebf53e4f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 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:00007fdebf4ec218 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 00007fdebf5cb3e8 RCX: 00007fdebf53e4f9
RDX: 00007fdebf53e4f9 RSI: 0000000000000000 RDI: 0000200000000280
RBP: 00007fdebf5cb3e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fdebf598034
R13: 0000200000008280 R14: 00007fdebf59600e R15: 0000200000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:traverse_mounts fs/namei.c:1459 [inline]
RIP: 0010:handle_mounts fs/namei.c:1571 [inline]
RIP: 0010:step_into+0x121/0xf50 fs/namei.c:1891
Code: 74 24 08 c6 44 24 7f 00 43 0f b6 04 3c 84 c0 4d 89 fd 0f 85 10 0c 00 00 45 8b 36 4c 8b bc 24 a8 00 00 00 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 0f 0c 00 00 45 8b 3f 44 89 fe 81 e6 00
RSP: 0018:ffffc900012afa80 EFLAGS: 00010207
RAX: 0000000000000003 RBX: ffffc900012afcc0 RCX: ffff88812e1c9300
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900012afb98 R08: ffff88813401129f R09: 1ffff11026802253
R10: dffffc0000000000 R11: ffffed1026802254 R12: 1ffff92000255f9f
R13: dffffc0000000000 R14: 0000000000000000 R15: 000000000000001d
FS:  00007fdebf4ec6c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055da7b71b388 CR3: 0000000101f0e000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	74 24                	je     0x26
   2:	08 c6                	or     %al,%dh
   4:	44 24 7f             	rex.R and $0x7f,%al
   7:	00 43 0f             	add    %al,0xf(%rbx)
   a:	b6 04                	mov    $0x4,%dh
   c:	3c 84                	cmp    $0x84,%al
   e:	c0 4d 89 fd          	rorb   $0xfd,-0x77(%rbp)
  12:	0f 85 10 0c 00 00    	jne    0xc28
  18:	45 8b 36             	mov    (%r14),%r14d
  1b:	4c 8b bc 24 a8 00 00 	mov    0xa8(%rsp),%r15
  22:	00
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 0f 0c 00 00    	jne    0xc46
  37:	45 8b 3f             	mov    (%r15),%r15d
  3a:	44 89 fe             	mov    %r15d,%esi
  3d:	81                   	.byte 0x81
  3e:	e6 00                	out    %al,$0x0