syzbot

Oops: general protection fault, probably for non-canonical address 0xdffffc00000000c7: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000638-0x000000000000063f]
CPU: 0 UID: 0 PID: 5293 Comm: kworker/0:4 Not tainted 6.12.0-rc2-next-20241008-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events_long flush_mdb
RIP: 0010:hfs_mdb_commit+0x37/0xfd0 fs/hfs/mdb.c:266
Code: 53 48 83 ec 48 48 89 fb 49 bd 00 00 00 00 00 fc ff df e8 9c 85 0a ff 48 89 5c 24 08 4c 8d a3 38 06 00 00 4c 89 e3 48 c1 eb 03 <42> 80 3c 2b 00 74 08 4c 89 e7 e8 aa 3c 74 ff 4d 8b 34 24 49 8d 6e
RSP: 0018:ffffc90003c4fb40 EFLAGS: 00010202
RAX: ffffffff828a6eb4 RBX: 00000000000000c7 RCX: ffff88806556da00
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
RBP: ffffc90003c4fdc0 R08: ffff888068ad61eb R09: 1ffff1100d15ac3d
R10: dffffc0000000000 R11: ffffed100d15ac3e R12: 0000000000000638
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000800000
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2b6997 CR3: 000000006c7c8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:hfs_mdb_commit+0x37/0xfd0 fs/hfs/mdb.c:266
Code: 53 48 83 ec 48 48 89 fb 49 bd 00 00 00 00 00 fc ff df e8 9c 85 0a ff 48 89 5c 24 08 4c 8d a3 38 06 00 00 4c 89 e3 48 c1 eb 03 <42> 80 3c 2b 00 74 08 4c 89 e7 e8 aa 3c 74 ff 4d 8b 34 24 49 8d 6e
RSP: 0018:ffffc90003c4fb40 EFLAGS: 00010202
RAX: ffffffff828a6eb4 RBX: 00000000000000c7 RCX: ffff88806556da00
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
RBP: ffffc90003c4fdc0 R08: ffff888068ad61eb R09: 1ffff1100d15ac3d
R10: dffffc0000000000 R11: ffffed100d15ac3e R12: 0000000000000638
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000800000
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0aae88ef98 CR3: 000000004d060000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	53                   	push   %rbx
   1:	48 83 ec 48          	sub    $0x48,%rsp
   5:	48 89 fb             	mov    %rdi,%rbx
   8:	49 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%r13
   f:	fc ff df
  12:	e8 9c 85 0a ff       	call   0xff0a85b3
  17:	48 89 5c 24 08       	mov    %rbx,0x8(%rsp)
  1c:	4c 8d a3 38 06 00 00 	lea    0x638(%rbx),%r12
  23:	4c 89 e3             	mov    %r12,%rbx
  26:	48 c1 eb 03          	shr    $0x3,%rbx
* 2a:	42 80 3c 2b 00       	cmpb   $0x0,(%rbx,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 e7             	mov    %r12,%rdi
  34:	e8 aa 3c 74 ff       	call   0xff743ce3
  39:	4d 8b 34 24          	mov    (%r12),%r14
  3d:	49                   	rex.WB
  3e:	8d                   	.byte 0x8d
  3f:	6e                   	outsb  %ds:(%rsi),(%dx)