Date: Sat, 20 Feb 2010 12:04:35 +0000 (UTC) From: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> To: Mikolaj Golub <to.my.trociny@gmail.com> Cc: freebsd-net@freebsd.org Subject: Re: mpd has hung Message-ID: <20100220115850.T27327@maildrop.int.zabbadoz.net> In-Reply-To: <20100220112639.L27327@maildrop.int.zabbadoz.net> References: <20100217132632.GA756@crete.org.ua> <4B7D5D95.20007@gmx.com> <86bpflqr5b.fsf@zhuzha.ua1> <20100220112639.L27327@maildrop.int.zabbadoz.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, 20 Feb 2010, Bjoern A. Zeeb wrote: > On Fri, 19 Feb 2010, Mikolaj Golub wrote: > >> On Thu, 18 Feb 2010 17:32:37 +0200 Nikos Vassiliadis wrote: >> >>> On 2/17/2010 3:26 PM, Alexander Shikoff wrote: >>>> Hello All, >>>> >>>> I have mpd 5.3 running on 8.0-RC1 as PPPoE server (now only 5 clients). >>>> Today mpd process hung and I cannot kill it with -9 signal, and I cannot >>>> access it's console via telnet. >>>> >>>> State of process in `top` output is STOP: >>>> 73551 root 2 44 0 29588K 5692K STOP 6 0:32 0.00% mpd5 >>>> >>>> # procstat -kk 73551 >>>> PID TID COMM TDNAME KSTACK >>>> 73551 100233 mpd5 - mi_switch+0x16f >>>> sleepq_wait+0x42 _cv_wait+0x111 flowtable_flush+0x51 if_detach+0x2f2 >>>> ng_iface_shutdown+0x1e ng_rmnode+0x167 ng_apply_item+0xef7 >>>> ng_snd_item+0x2ce ngc_send+0x1d2 sosend_generic+0x3f6 kern_sendit+0x13d >>>> sendit+0xdc sendto+0x4d syscall+0x1da Xfast_syscall+0xe1 >>>> 73551 100502 mpd5 - mi_switch+0x16f >>>> thread_suspend_switch+0xc6 thread_single+0x1b6 exit1+0x72 sigexit+0x7c >>>> postsig+0x306 ast+0x279 doreti_ast+0x1f >>>> >>>> Is there a way to stop a process without rebooting a whole system? >>>> Thanks in advance! >>>> >>>> P.S. I'm ready for experiments with it before tonight, but I cannot >>>> force system to crash in order to get crash dump right now. >>>> >>> >>> It's probably too late now, but are you sure that nobody pressed >>> CTLR-Z while in the mpd console??? >>> >>> CTLR-Z will send SIGSTOP to the process and the process will >>> stop. While stopped, all processing stops(including receiving >>> SIGKILL, you cannot kill it, and the signals are queued). You >>> have to send SIGCONT for the process to continue. >> >> We were discussing this problem with Alexander in another >> (Russian/Ukrainian >> speaking) maillist. And it looks like the problem is the following. >> >> mpd5 thread was detaching ng interface and when doing flowtable_flush() it >> slept in cv_wait waiting for flowclean_cycles variable to be updated. It >> should have been awaken by flowcleaner thread but this thread got stuck in >> endless loop, supposedly in flowtable_clean_vnet()/flowtable_free_stale(), >> I >> think because of inconsistent state of some lists (iface?) due to if_detach >> being in progress. > > I have patches that are out for review. I am not sure if they apply cleanly as they are broken out of the tail side of a larger patchset. If you are not using VIMAGEs you could ignore the ones I marked with (*). http://people.freebsd.org/~bz/20100216-10-ft-cv.diff http://people.freebsd.org/~bz/20100216-11-ft-debugging.diff http://people.freebsd.org/~bz/20100216-12-ft-cleanup.diff (*) http://people.freebsd.org/~bz/20100216-13-ft-ll-cleanup.diff http://people.freebsd.org/~bz/20100216-18-ft-free.diff (*) If you are still seeing the hang and have DDB support in your kernel, then break into the debugger and save the complete output of ddb> ps before rebooting. Regards, Bjoern -- Bjoern A. Zeeb It will not break if you know what you are doing.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20100220115850.T27327>