[syzbot] [serial?] general protection fault in to_utf8

[syzbot <syzbot+3f83d97f1d51ddaabd8a@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    615aad0f61e0 Add linux-next specific files for 20260126
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=147b432a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d51c584a7396ddf1
dashboard link: https://syzkaller.appspot.com/bug?extid=3f83d97f1d51ddaabd8a
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16201fb3980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11bba802580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5318e5f027be/disk-615aad0f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d165e561fa49/vmlinux-615aad0f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fb0e01c90aa5/bzImage-615aad0f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3f83d97f1d51ddaabd8a@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]
CPU: 1 UID: 0 PID: 6053 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
RIP: 0010:__queue_work+0xa2/0xf90 kernel/workqueue.c:2269
Code: 11 31 ff 89 ee e8 4e f4 37 00 85 ed 0f 85 ef 0c 00 00 e8 01 f0 37 00 4d 8d b7 c0 01 00 00 4c 89 f0 48 c1 e8 03 48 89 44 24 28 <42> 0f b6 04 20 84 c0 0f 85 22 0d 00 00 4c 89 34 24 41 8b 2e 89 ee
RSP: 0018:ffffc900036c7318 EFLAGS: 00010002
RAX: 0000000000000038 RBX: 0000000000000008 RCX: ffff88802f848000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88813ff72017 R09: 1ffff11027fee402
R10: dffffc0000000000 R11: ffffed1027fee403 R12: dffffc0000000000
R13: ffff88813ff72010 R14: 00000000000001c0 R15: 0000000000000000
FS:  0000555556b5d500(0000) GS:ffff8881253b4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31663fff CR3: 0000000075e7c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 queue_work_on+0x106/0x1d0 kernel/workqueue.c:2405
 put_queue drivers/tty/vt/keyboard.c:328 [inline]
 to_utf8+0x872/0x1ad0 drivers/tty/vt/keyboard.c:-1
 put_queue_utf8 drivers/tty/vt/keyboard.c:382 [inline]
 k_unicode drivers/tty/vt/keyboard.c:683 [inline]
 k_self+0x326/0x7e0 drivers/tty/vt/keyboard.c:701
 kbd_keycode drivers/tty/vt/keyboard.c:1497 [inline]
 kbd_event+0x2ec1/0x40d0 drivers/tty/vt/keyboard.c:1515
 input_handle_events_default+0xd4/0x1a0 drivers/input/input.c:2541
 input_pass_values+0x288/0x890 drivers/input/input.c:128
 input_event_dispose+0x330/0x6b0 drivers/input/input.c:342
 input_inject_event+0x1dd/0x340 drivers/input/input.c:424
 evdev_write+0x325/0x4c0 drivers/input/evdev.c:528
 vfs_write+0x29a/0xb90 fs/read_write.c:686
 ksys_write+0x150/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa3fd19aeb9
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:00007fffb1030708 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa3fd415fa0 RCX: 00007fa3fd19aeb9
RDX: 0000000000002250 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 00007fa3fd208c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa3fd415fac R14: 00007fa3fd415fa0 R15: 00007fa3fd415fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__queue_work+0xa2/0xf90 kernel/workqueue.c:2269
Code: 11 31 ff 89 ee e8 4e f4 37 00 85 ed 0f 85 ef 0c 00 00 e8 01 f0 37 00 4d 8d b7 c0 01 00 00 4c 89 f0 48 c1 e8 03 48 89 44 24 28 <42> 0f b6 04 20 84 c0 0f 85 22 0d 00 00 4c 89 34 24 41 8b 2e 89 ee
RSP: 0018:ffffc900036c7318 EFLAGS: 00010002
RAX: 0000000000000038 RBX: 0000000000000008 RCX: ffff88802f848000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88813ff72017 R09: 1ffff11027fee402
R10: dffffc0000000000 R11: ffffed1027fee403 R12: dffffc0000000000
R13: ffff88813ff72010 R14: 00000000000001c0 R15: 0000000000000000
FS:  0000555556b5d500(0000) GS:ffff8881253b4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31663fff CR3: 0000000075e7c000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	31 ff                	xor    %edi,%edi
   2:	89 ee                	mov    %ebp,%esi
   4:	e8 4e f4 37 00       	call   0x37f457
   9:	85 ed                	test   %ebp,%ebp
   b:	0f 85 ef 0c 00 00    	jne    0xd00
  11:	e8 01 f0 37 00       	call   0x37f017
  16:	4d 8d b7 c0 01 00 00 	lea    0x1c0(%r15),%r14
  1d:	4c 89 f0             	mov    %r14,%rax
  20:	48 c1 e8 03          	shr    $0x3,%rax
  24:	48 89 44 24 28       	mov    %rax,0x28(%rsp)
* 29:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	0f 85 22 0d 00 00    	jne    0xd58
  36:	4c 89 34 24          	mov    %r14,(%rsp)
  3a:	41 8b 2e             	mov    (%r14),%ebp
  3d:	89 ee                	mov    %ebp,%esi


---
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