syzbot

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 5180 Comm: kworker/1:1 Not tainted 6.7.0-rc6-next-20231222-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Workqueue: pm pm_runtime_work
RIP: 0010:serial8250_tx_chars+0x3bb/0x890 drivers/tty/serial/8250/8250_port.c:1809
Code: 02 00 00 e8 77 db a6 fc 48 8b 44 24 30 80 38 00 0f 85 15 04 00 00 4d 03 a5 a0 03 00 00 4c 89 e0 4c 89 e2 48 c1 e8 03 83 e2 07 <0f> b6 04 28 38 d0 7f 08 84 c0 0f 85 a3 03 00 00 48 8b 44 24 18 41
RSP: 0018:ffffc900042bf9f0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff92cb01c0 RCX: ffffffff92cb046c
RDX: 0000000000000000 RSI: ffffffff84e13849 RDI: ffffffff92cb0470
RBP: dffffc0000000000 R08: 0000000000000004 R09: ffffffff92cb02e4
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88801dd60c30 R14: 0000000000000010 R15: ffff88801debd158
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020404030 CR3: 000000000cf78000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __start_tx+0x3cb/0x480 drivers/tty/serial/8250/8250_port.c:1544
 serial8250_start_tx+0x35d/0x530 drivers/tty/serial/8250/8250_port.c:1653
 serial_port_runtime_resume+0x29e/0x330 drivers/tty/serial/serial_port.c:40
 __rpm_callback+0xc5/0x4c0 drivers/base/power/runtime.c:393
 rpm_callback+0x1d6/0x220 drivers/base/power/runtime.c:447
 rpm_resume+0xdc7/0x1990 drivers/base/power/runtime.c:913
 pm_runtime_work+0x12e/0x180 drivers/base/power/runtime.c:978
 process_one_work+0x8a4/0x15f0 kernel/workqueue.c:2633
 process_scheduled_works kernel/workqueue.c:2706 [inline]
 worker_thread+0x8b6/0x1290 kernel/workqueue.c:2787
 kthread+0x2c1/0x3a0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:serial8250_tx_chars+0x3bb/0x890 drivers/tty/serial/8250/8250_port.c:1809
Code: 02 00 00 e8 77 db a6 fc 48 8b 44 24 30 80 38 00 0f 85 15 04 00 00 4d 03 a5 a0 03 00 00 4c 89 e0 4c 89 e2 48 c1 e8 03 83 e2 07 <0f> b6 04 28 38 d0 7f 08 84 c0 0f 85 a3 03 00 00 48 8b 44 24 18 41
RSP: 0018:ffffc900042bf9f0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff92cb01c0 RCX: ffffffff92cb046c
RDX: 0000000000000000 RSI: ffffffff84e13849 RDI: ffffffff92cb0470
RBP: dffffc0000000000 R08: 0000000000000004 R09: ffffffff92cb02e4
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88801dd60c30 R14: 0000000000000010 R15: ffff88801debd158
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020404030 CR3: 000000000cf78000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	02 00                	add    (%rax),%al
   2:	00 e8                	add    %ch,%al
   4:	77 db                	ja     0xffffffe1
   6:	a6                   	cmpsb  %es:(%rdi),%ds:(%rsi)
   7:	fc                   	cld
   8:	48 8b 44 24 30       	mov    0x30(%rsp),%rax
   d:	80 38 00             	cmpb   $0x0,(%rax)
  10:	0f 85 15 04 00 00    	jne    0x42b
  16:	4d 03 a5 a0 03 00 00 	add    0x3a0(%r13),%r12
  1d:	4c 89 e0             	mov    %r12,%rax
  20:	4c 89 e2             	mov    %r12,%rdx
  23:	48 c1 e8 03          	shr    $0x3,%rax
  27:	83 e2 07             	and    $0x7,%edx
* 2a:	0f b6 04 28          	movzbl (%rax,%rbp,1),%eax <-- trapping instruction
  2e:	38 d0                	cmp    %dl,%al
  30:	7f 08                	jg     0x3a
  32:	84 c0                	test   %al,%al
  34:	0f 85 a3 03 00 00    	jne    0x3dd
  3a:	48 8b 44 24 18       	mov    0x18(%rsp),%rax
  3f:	41                   	rex.B