warn_on_slowpath

[Wolfgang Rohdewald <wolfgang@xxxxxxxxxxxx>]

Hi,

this is a 2.6.26 kernel. I have an AV Receiver connected via RS-232C,
using a USB-RS232C adapter. If I send a command upon which the
receiver answers, I am getting this backtrace.

This works:
cat /dev/ttyUSB0 &
echo PW? > /dev/ttyUSB0
PWON

where PWON is the answer.
If I omit the cat, thusly ignoring the returned data, I am getting the
backtrace.

lsusb says
Bus 003 Device 002: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port


Sep  3 12:02:46 server kernel: [ 6462.211557] ------------[ cut here ]------------
Sep  3 12:02:46 server kernel: [ 6462.211625] WARNING: at drivers/usb/serial/usb-serial.c:319 serial_write_room+0x44/0x53 [usbserial]()
Sep  3 12:02:46 server kernel: re]
Sep  3 12:02:46 server kernel: [ 6462.216570] Pid: 10, comm: events/1 Tainted: G        W 2.6.26woro9 #1
Sep  3 12:02:46 server kernel: [ 6462.216570]  [<c0121739>] warn_on_slowpath+0x41/0x7b
Sep  3 12:02:46 server kernel: [ 6462.216570]  [<c01d7e6e>] ? number+0x106/0x1c0
Sep  3 12:02:46 server kernel: [ 6462.216570]  [<c01081d1>] ? read_tsc+0x9/0x26
Sep  3 12:02:46 server kernel: [ 6462.216570]  [<c0136083>] ? getnstimeofday+0x37/0xb9
Sep  3 12:02:46 server kernel: [ 6462.216570]  [<c01344a2>] ? ktime_get_ts+0x40/0x44
Sep  3 12:02:46 server kernel: [ 6462.216713]  [<c01344b9>] ? ktime_get+0x13/0x2f
Sep  3 12:02:46 server kernel: [ 6462.216852]  [<f8926471>] serial_write_room+0x44/0x53 [usbserial]
Sep  3 12:02:46 server kernel: [ 6462.216961]  [<c021d92f>] tty_write_room+0x18/0x1a
Sep  3 12:02:46 server kernel: [ 6462.217063]  [<c021badf>] opost+0x14/0x1bb
Sep  3 12:02:46 server kernel: [ 6462.217164]  [<c021bcd5>] echo_char+0x4f/0x53
Sep  3 12:02:46 server kernel: [ 6462.217263]  [<c021cc2f>] n_tty_receive_buf+0x3d9/0xff5
Sep  3 12:02:46 server kernel: [ 6462.217389]  [<c011951f>] ? dequeue_task_fair+0x3d/0x42
Sep  3 12:02:46 server kernel: [ 6462.217527]  [<c011d528>] ? hrtick_set+0x80/0xe5
Sep  3 12:02:46 server kernel: [ 6462.217667]  [<c02aaf23>] ? schedule+0x7f2/0x833
Sep  3 12:02:46 server kernel: [ 6462.217806]  [<c011641f>] ? __wake_up_common+0x35/0x5b
Sep  3 12:02:46 server kernel: [ 6462.217947]  [<c0217ea3>] ? tty_ldisc_try+0x30/0x36
Sep  3 12:02:46 server kernel: [ 6462.218087]  [<c02183d4>] flush_to_ldisc+0xda/0x16a
Sep  3 12:02:46 server kernel: [ 6462.218193]  [<c02182fa>] ? flush_to_ldisc+0x0/0x16a
Sep  3 12:02:46 server kernel: [ 6462.218329]  [<c012e91f>] run_workqueue+0x72/0xe7
Sep  3 12:02:46 server kernel: [ 6462.218431]  [<c012ea16>] worker_thread+0x82/0x8e
Sep  3 12:02:46 server kernel: [ 6462.218532]  [<c0131667>] ? autoremove_wake_function+0x0/0x33
Sep  3 12:02:46 server kernel: [ 6462.218672]  [<c012e994>] ? worker_thread+0x0/0x8e
Sep  3 12:02:46 server kernel: [ 6462.218809]  [<c01313f8>] kthread+0x3b/0x61
Sep  3 12:02:46 server kernel: [ 6462.218907]  [<c01313bd>] ? kthread+0x0/0x61
Sep  3 12:02:46 server kernel: [ 6462.219044]  [<c01044e7>] kernel_thread_helper+0x7/0x10
Sep  3 12:02:46 server kernel: [ 6462.219148]  =======================
Sep  3 12:02:46 server kernel: [ 6462.219206] ---[ end trace fc3efcd97d069eed ]---
Sep  3 12:02:46 server kernel: [ 6462.219273] ------------[ cut here ]------------
Sep  3 12:02:46 server kernel: [ 6462.219335] WARNING: at drivers/usb/serial/usb-serial.c:306 serial_write+0x5e/0x79 [usbserial]()
Sep  3 12:02:46 server kernel: re]
Sep  3 12:02:46 server kernel: [ 6462.224568] Pid: 10, comm: events/1 Tainted: G        W 2.6.26woro9 #1
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c0121739>] warn_on_slowpath+0x41/0x7b
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c01d7e6e>] ? number+0x106/0x1c0
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c01081d1>] ? read_tsc+0x9/0x26
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c0136083>] ? getnstimeofday+0x37/0xb9
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<f89264de>] serial_write+0x5e/0x79 [usbserial]
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c02179b6>] tty_put_char+0x26/0x2a
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c021bc71>] opost+0x1a6/0x1bb
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c021bcd5>] echo_char+0x4f/0x53
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c021cc2f>] n_tty_receive_buf+0x3d9/0xff5
Sep  3 12:02:46 server kernel: [ 6462.224568]  [<c011951f>] ? dequeue_task_fair+0x3d/0x42
Sep  3 12:02:46 server kernel: [ 6462.224713]  [<c011d528>] ? hrtick_set+0x80/0xe5
Sep  3 12:02:46 server kernel: [ 6462.224852]  [<c02aaf23>] ? schedule+0x7f2/0x833
Sep  3 12:02:46 server kernel: [ 6462.224991]  [<c011641f>] ? __wake_up_common+0x35/0x5b
Sep  3 12:02:46 server kernel: [ 6462.225132]  [<c0217ea3>] ? tty_ldisc_try+0x30/0x36
Sep  3 12:02:46 server kernel: [ 6462.225270]  [<c02183d4>] flush_to_ldisc+0xda/0x16a
Sep  3 12:02:46 server kernel: [ 6462.225378]  [<c02182fa>] ? flush_to_ldisc+0x0/0x16a
Sep  3 12:02:46 server kernel: [ 6462.225515]  [<c012e91f>] run_workqueue+0x72/0xe7
Sep  3 12:02:46 server kernel: [ 6462.225616]  [<c012ea16>] worker_thread+0x82/0x8e
Sep  3 12:02:46 server kernel: [ 6462.225717]  [<c0131667>] ? autoremove_wake_function+0x0/0x33
Sep  3 12:02:46 server kernel: [ 6462.225856]  [<c012e994>] ? worker_thread+0x0/0x8e
Sep  3 12:02:46 server kernel: [ 6462.225993]  [<c01313f8>] kthread+0x3b/0x61
Sep  3 12:02:46 server kernel: [ 6462.226092]  [<c01313bd>] ? kthread+0x0/0x61
Sep  3 12:02:46 server kernel: [ 6462.226226]  [<c01044e7>] kernel_thread_helper+0x7/0x10
Sep  3 12:02:46 server kernel: [ 6462.226332]  =======================
Sep  3 12:02:46 server kernel: [ 6462.226390] ---[ end trace fc3efcd97d069eed ]---


-- 
Wolfgang
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