------------[ cut here ]------------
WARNING: at drivers/usb/serial/usb-serial.c:406 serial_write_room+0x6c/0x84()
Modules linked in:
Backtrace:
[<c0035270>] (dump_backtrace+0x0/0x10c) from [<c0397c60>] (dump_stack+0x18/0x1c)
r7:00000000 r6:c02023bc r5:c047e330 r4:00000196
[<c0397c48>] (dump_stack+0x0/0x1c) from [<c004a0bc>] (warn_slowpath_common+0x4c/0x80)
[<c004a070>] (warn_slowpath_common+0x0/0x80) from [<c004a108>] (warn_slowpath_null+0x18/0x1c)
r7:00000000 r6:c3cb2c00 r5:c3cb2c00 r4:c3bb7e00
[<c004a0f0>] (warn_slowpath_null+0x0/0x1c) from [<c02023bc>] (serial_write_room+0x6c/0x84)
[<c0202350>] (serial_write_room+0x0/0x84) from [<c016dd60>] (tty_write_room+0x28/0x2c)
r5:c3c679c0 r4:00000000
[<c016dd38>] (tty_write_room+0x0/0x2c) from [<c016b3fc>] (process_echoes+0x50/0x2ac)
[<c016b3ac>] (process_echoes+0x0/0x2ac) from [<c016ceb4>] (n_tty_receive_buf+0x448/0x11a4)
[<c016ca6c>] (n_tty_receive_buf+0x0/0x11a4) from [<c017009c>] (flush_to_ldisc+0x184/0x1a4)
[<c016ff18>] (flush_to_ldisc+0x0/0x1a4) from [<c005b5e0>] (worker_thread+0x10c/0x1ac)
r9:00000000 r8:c3800368 r7:00000000 r6:c382c000 r5:c016ff18
r4:c3800360
[<c005b4d4>] (worker_thread+0x0/0x1ac) from [<c005ef90>] (kthread+0x88/0x90)
[<c005ef08>] (kthread+0x0/0x90) from [<c004d2cc>] (do_exit+0x0/0x62c)
r6:00000000 r5:00000000 r4:00000000
---[ end trace 10a24e43328e8544 ]---
USB串口的问题，看不出什么名堂来。换一个内核版本试试看。
