==> Regarding Re: [Wlug] HOWTO debug hard lockups; Eric Martin <freak4uxxx@gmail.com> adds: freak4uxxx> Right, I forgot about that jeff. If you're running syslog-ng, freak4uxxx> you can go into /etc/syslog-ng/syslog-ng.conf and add a line: freak4uxxx> destination console_all { ("/dev/ttyS01"); }; freak4uxxx> although, I'm not sure if you're locking up if syslog-ng will freak4uxxx> keep scrolling. I don't know if netcat (nc) will either... syslog-ng is user space. The kernel should do all of its console writes itself. Your suggestion does not help in the hung system case. Netcat, used as I described (on the system that is receiving messages), is fine. The kernel is outputting the log messages over the network via the netpoll infrastructure. That infrastructure can function even when the system is not servicing interrupts. -Jeff freak4uxxx> On 6/21/05, Jeff Moyer <jmoyer@redhat.com> wrote:
==> Regarding Re: [Wlug] HOWTO debug hard lockups; Andy Stewart < andystewart@comcast.net> adds:
andystewart> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
andystewart> Jeff Moyer wrote:
==> Regarding Re: [Wlug] HOWTO debug hard lockups; Andy Stewart >> <andystewart@comcast.net> adds:
andystewart> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
andystewart> Eric Martin wrote:
In reguards to seeing messages on minicom, what logger do you have installed? Can you just shovel kernel messages over to ttyS01? eg sudo tailf /var/log/kernel ttyS01
Umm, it works just fine so long as the system is up and running. You really want the kernel to be printing directly to the console. >> Otherwise, when the system locks up and the NMI fires, you still won't get your messages over the serial console.
Andy, it looked to me like you had things configured
andystewart> I did that per your suggestion and it works just fine. properly. Indeed, >> I use a very similar setup all of the time. The only difference is it >> works for me. (I hate that phrase).
I'm not sure what to suggest at this point. If you do an alt-sysrq-h, does that at least print out over the serial console?
-Jeff
andystewart> HI Jeff,
andystewart> If I do an alt-sysrq-h, I get the one line help on the serial andystewart> console. If I do alt-sysrq-m to show memory, I see "SysRq : andystewart> Show Memory" ont the serial console, but nothing more (unless andystewart> I use Eric's trick). If I go to runlevel 1, alt-sysrq-m has andystewart> the entire output on the serial console.
You have all of the luck. How about trying netconsole? It's easy enough to setup. On the host which will receive the logs, do something like this:
nc -u -l -p 6666
On the problematic system, load the netconsole module:
modprobe netconsole netconsole=@<ip-of-this-machine>/<ethX>,6666@<ip-of-server>/<MAC-address-of-server>
You can try this or not, depending on whether you still experience crashes. It sounds like the latest kernel fixed things right up for you, right?
Oh well, good to have in your bag of tricks, I guess.
-Jeff _______________________________________________ Wlug mailing list Wlug@mail.wlug.org http://mail.wlug.org/mailman/listinfo/wlug
freak4uxxx> Right, I forgot about that jeff. If you're running freak4uxxx> syslog-ng, you can go into /etc/syslog-ng/syslog-ng.conf and freak4uxxx> add a line:<br> <br> <div style="margin-left: 40px;"><span freak4uxxx> style="font-style: italic;">destination console_all { freak4uxxx> ("/dev/ttyS01"); };<br> </span></div> <br> although, freak4uxxx> I'm not sure if you're locking up if syslog-ng will keep freak4uxxx> scrolling. I don't know if netcat (nc) will freak4uxxx> either...<span style="font-style: italic;"></span><br> <span freak4uxxx> style="font-style: italic;"></span><br><div><span freak4uxxx> class="gmail_quote">On 6/21/05, <b freak4uxxx> class="gmail_sendername">Jeff Moyer</b> <<a freak4uxxx> href="mailto:jmoyer@redhat.com">jmoyer@redhat.com</a>> freak4uxxx> wrote:</span><blockquote class="gmail_quote" freak4uxxx> style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt freak4uxxx> 0pt 0pt 0.8ex; padding-left: 1ex;"> ==> Regarding Re: [Wlug] freak4uxxx> HOWTO debug hard lockups; Andy Stewart <<a freak4uxxx> href="mailto:andystewart@comcast.net">andystewart@comcast.net</a>> freak4uxxx> adds:<br><br>andystewart> -----BEGIN PGP SIGNED MESSAGE----- freak4uxxx> Hash: SHA1<br> <br>andystewart> Jeff Moyer freak4uxxx> wrote:<br>>> ==> Regarding Re: [Wlug] HOWTO debug hard freak4uxxx> lockups; Andy Stewart<br>>> <<a freak4uxxx> href="mailto:andystewart@comcast.net">andystewart@comcast.net</a>> freak4uxxx> adds:<br>>> <br>andystewart> -----BEGIN PGP SIGNED freak4uxxx> MESSAGE----- Hash: SHA1<br>>><br>andystewart> Eric freak4uxxx> Martin wrote:<br>>>>> In reguards to seeing freak4uxxx> messages on minicom, what logger do you freak4uxxx> have<br>>>>> installed? Can you just freak4uxxx> shovel kernel messages over to ttyS01? eg freak4uxxx> <br>>>>> sudo tailf /var/log/kernel freak4uxxx> ttyS01<br>>><br>andystewart> I did that per your freak4uxxx> suggestion and it works just fine.<br>>> Umm, it works freak4uxxx> just fine so long as the system is up and freak4uxxx> running. You <br>>> really want the kernel to freak4uxxx> be printing directly to the console.<br>>> Otherwise, freak4uxxx> when the system locks up and the NMI fires, you still freak4uxxx> won't<br>>> get your messages over the serial freak4uxxx> console.<br>>> <br>>> Andy, it looked to me like freak4uxxx> you had things configured freak4uxxx> properly. Indeed,<br>>> I use a very similar freak4uxxx> setup all of the time. The only difference is freak4uxxx> it<br>>> works for me. (I hate that freak4uxxx> phrase).<br>>> <br>>> I'm not sure what to suggest freak4uxxx> at this point. If you do an alt-sysrq-h,<br>>> freak4uxxx> does that at least print out over the serial freak4uxxx> console?<br>>><br>>> freak4uxxx> -Jeff<br>>><br><br>andystewart> HI Jeff, freak4uxxx> <br><br>andystewart> If I do an alt-sysrq-h, I get the one freak4uxxx> line help on the serial<br>andystewart> freak4uxxx> console. If I do alt-sysrq-m to show memory, I see freak4uxxx> "SysRq :<br>andystewart> Show Memory" ont the freak4uxxx> serial console, but nothing more (unless <br>andystewart> I freak4uxxx> use Eric's trick). If I go to runlevel 1, freak4uxxx> alt-sysrq-m has<br>andystewart> the entire output on the freak4uxxx> serial console.<br><br>You have all of the luck. How freak4uxxx> about trying netconsole? It's easy enough <br>to freak4uxxx> setup. On the host which will receive the logs, do freak4uxxx> something like this:<br><br>nc -u -l -p 6666<br><br>On the freak4uxxx> problematic system, load the netconsole module:<br><br>modprobe freak4uxxx> netconsole freak4uxxx> netconsole=@<ip-of-this-machine>/<ethX>,6666@<ip-of-server>/<MAC-address-of-server> freak4uxxx> <br><br><br>You can try this or not, depending on whether you freak4uxxx> still experience<br>crashes. It sounds like the freak4uxxx> latest kernel fixed things right up for freak4uxxx> you,<br>right?<br><br>Oh well, good to have in your bag of freak4uxxx> tricks, I guess. freak4uxxx> <br><br>-Jeff<br>_______________________________________________<br>Wlug freak4uxxx> mailing list<br><a freak4uxxx> href="mailto:Wlug@mail.wlug.org">Wlug@mail.wlug.org</a><br><a freak4uxxx> href="http://mail.wlug.org/mailman/listinfo/wlug">http://mail.wlug.org/mailman/listinfo/wlug freak4uxxx> </a><br></blockquote></div><br>