[syzbot] [serial?] WARNING in uart_write

[syzbot <syzbot+a38f8e1908608d337bb3@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    124cfbcd6d18 Add linux-next specific files for 20240521
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12341062980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2c3a67a38201bdf7
dashboard link: https://syzkaller.appspot.com/bug?extid=a38f8e1908608d337bb3
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ff8e45d8b821/disk-124cfbcd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6aeeec759cde/vmlinux-124cfbcd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9e7d931d0a4b/bzImage-124cfbcd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a38f8e1908608d337bb3@syzkaller.appspotmail.com

sp0: Synchronizing with TNC
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5215 at drivers/tty/serial/serial_core.c:625 uart_write+0x2b0/0x320 drivers/tty/serial/serial_core.c:625
Modules linked in:
CPU: 0 PID: 5215 Comm: syz-executor.1 Not tainted 6.9.0-next-20240521-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:uart_write+0x2b0/0x320 drivers/tty/serial/serial_core.c:625
Code: 74 08 48 89 df e8 c0 5e bf fc 48 83 3b 00 74 74 e8 55 7a 59 fc eb 97 e8 4e 7a 59 fc 45 31 e4 eb 08 e8 44 7a 59 fc 45 31 ed 90 <0f> 0b 90 45 84 e4 74 0a e8 33 7a 59 fc 45 31 f6 eb 84 e8 29 7a 59
RSP: 0018:ffffc900047874b8 EFLAGS: 00010046
RAX: ffffffff853ceb62 RBX: dffffc0000000000 RCX: 0000000000040000
RDX: ffffc9000a14b000 RSI: 000000000001b0ec RDI: 000000000001b0ed
RBP: ffff888020728f48 R08: 0000000000000003 R09: fffff520008f0e74
R10: dffffc0000000000 R11: fffff520008f0e74 R12: 0000000000000000
R13: 0000000000000246 R14: ffff888020728be8 R15: ffffffff94adece0
FS:  00007f53ae0446c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1488dbcc98 CR3: 0000000079a6e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 tnc_init drivers/net/hamradio/6pack.c:531 [inline]
 sixpack_open+0x790/0xa80 drivers/net/hamradio/6pack.c:628
 tty_ldisc_open drivers/tty/tty_ldisc.c:432 [inline]
 tty_ldisc_reinit+0x2d4/0x4a0 drivers/tty/tty_ldisc.c:667
 tty_reopen+0x20b/0x2d0 drivers/tty/tty_io.c:1366
 tty_open_by_driver drivers/tty/tty_io.c:2082 [inline]
 tty_open+0xa26/0xdf0 drivers/tty/tty_io.c:2135
 chrdev_open+0x5b0/0x630 fs/char_dev.c:414
 do_dentry_open+0x95a/0x1720 fs/open.c:955
 do_open fs/namei.c:3650 [inline]
 path_openat+0x289f/0x3280 fs/namei.c:3807
 do_filp_open+0x235/0x490 fs/namei.c:3834
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1405
 do_sys_open fs/open.c:1420 [inline]
 __do_sys_openat fs/open.c:1436 [inline]
 __se_sys_openat fs/open.c:1431 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1431
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f53ad27cee9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f53ae0440c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f53ad3ac050 RCX: 00007f53ad27cee9
RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c
RBP: 00007f53ad2c949e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f53ad3ac050 R15: 00007ffc05d3f0d8
 </TASK>


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