------------[ cut here ]------------
WARNING: CPU: 1 PID: 6828 at drivers/tty/serial/serial_core.c:625 uart_write+0x2bf/0x3e0 drivers/tty/serial/serial_core.c:625
Modules linked in:
CPU: 1 PID: 6828 Comm: syz-executor.0 Not tainted 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:uart_write+0x2bf/0x3e0 drivers/tty/serial/serial_core.c:625
Code: 6b fc e9 4e ff ff ff e8 5f 03 91 fc 90 0f 0b 90 49 c7 c4 d2 ff ff ff e9 39 ff ff ff e8 4a 03 91 fc 45 31 ff e8 42 03 91 fc 90 <0f> 0b 90 48 85 ed 74 8c e8 34 03 91 fc 4c 8d a5 08 01 00 00 4c 89
RSP: 0018:ffffc9000410fa40 EFLAGS: 00010087
RAX: 000000000000cc4e RBX: ffff88801ffe8be8 RCX: ffffc900062dd000
RDX: 0000000000040000 RSI: ffffffff84fce20e RDI: ffff88801ffe8f48
RBP: ffffffff94de0f60 R08: 0000000000000001 R09: fffff52000821f36
R10: 0000000000000003 R11: ffffffff93950570 R12: 0000000000000001
R13: 0000000000000ffa R14: ffff888048f1c001 R15: 0000000000000287
FS:  00007f2fa06116c0(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32623000 CR3: 000000002560c000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ppp_async_push+0x89e/0x1740 drivers/net/ppp/ppp_async.c:666
 ppp_async_send+0xe5/0x120 drivers/net/ppp/ppp_async.c:634
 __ppp_channel_push+0xe5/0x230 drivers/net/ppp/ppp_generic.c:2150
 ppp_channel_push+0x1c2/0x250 drivers/net/ppp/ppp_generic.c:2177
 ppp_write+0x236/0x2e0 drivers/net/ppp/ppp_generic.c:525
 do_loop_readv_writev fs/read_write.c:764 [inline]
 do_loop_readv_writev fs/read_write.c:749 [inline]
 vfs_writev+0x6ec/0xde0 fs/read_write.c:973
 do_pwritev fs/read_write.c:1072 [inline]
 __do_sys_pwritev fs/read_write.c:1119 [inline]
 __se_sys_pwritev fs/read_write.c:1114 [inline]
 __x64_sys_pwritev+0x22b/0x310 fs/read_write.c:1114
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2f9f87cee9
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:00007f2fa06110c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 00007f2f9f9abf80 RCX: 00007f2f9f87cee9
RDX: 0000000000000002 RSI: 0000000020000380 RDI: 0000000000000004
RBP: 00007f2f9f8c949e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f2f9f9abf80 R15: 00007ffe118e3238
 </TASK>