From: arnd@arndb.de
To: Ales Teska <ales.teska@gmail.com>
Cc: linux-kernel@vger.kernel.org, Greg KH <gregkh@suse.de>,
Alan Cox <alan@linux.intel.com>
Subject: Re: PROBLEM: PPP and other serial port related application hangs in kernel space
Date: Wed, 9 Jun 2010 23:16:32 +0200 [thread overview]
Message-ID: <201006092316.32497.arnd@arndb.de> (raw)
In-Reply-To: <900E3B14-5B92-4A37-9581-049DB40F4D1C@gmail.com>
On Wednesday 09 June 2010 22:46:28 Ales Teska wrote:
> after upgrade of Linux kernel to version 2.6.34 I started to observe following problem
> - ppp and other serial port related application occasionally (in 1 hour or 1/10 ppp
> connections) 'hangs' (see description bellow) rendering related serial device unusable.
> I backtracked this issue to 2.6.32.15.
> Application remains in the condition marked as 'D' in 'ps' output (waiting for result
> from kernel space, if I understand that correctly); it stays in this condition forever.
It would be good to find out where exactly the application hangs. Please try a sysrq-t
(press Alt+SysRq+t simultaneously) or cat /proc/<pid-that-hangs>/stack.
It might also be helpful to try running the kernel with CONFIG_LOCKDEP and/or
CONFIG_TTY_MUTEX enabled. For the latter one, you need to get the source
from the tty branch of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl.git
> I also found following information in dmesg:
> [ 1673.660876] ------------[ cut here ]------------
> [ 1673.661471] WARNING: at drivers/char/tty_io.c:1278 tty_open+0x213/0x451()
> [ 1673.662358] Modules linked in: ppp_deflate zlib_deflate bsd_comp ppp_async crc_ccitt ppp_generic slhc ipv6 nvram msr cpuid ledtrig_timer ledtrig_heartbeat ledtrig_default_on geodewdt lm90 hwmon scx200_acb option usbserial ehci_hcd ohci_hcd via_rhine usbcore leds_alix2 mii
> [ 1673.689168] Pid: 1275, comm: ufoprobe_client Not tainted 2.6.34-486-exiprobes #1
> [ 1673.690452] Call Trace:
> [ 1673.690947] [<c10e93af>] ? tty_open+0x213/0x451
> [ 1673.691926] [<c1018f51>] warn_slowpath_common+0x45/0x5c
> [ 1673.693006] [<c1018f75>] warn_slowpath_null+0xd/0x10
> [ 1673.694293] [<c10e93af>] tty_open+0x213/0x451
> [ 1673.694755] [<c1068105>] chrdev_open+0xe3/0x126
Do you always see this message exactly once before it hangs?
Arnd
next prev parent reply other threads:[~2010-06-09 21:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-09 20:46 PROBLEM: PPP and other serial port related application hangs in kernel space Ales Teska
2010-06-09 21:16 ` arnd [this message]
2010-06-11 0:04 ` Ales Teska
2010-06-14 14:38 ` Maciej Rutecki
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