Re: 2.6.21-rc2-mm1

Andrew Morton
2007-03-04T11:34:55Z

On Sun, 4 Mar 2007 10:07:31 +0100 Mariusz Kozlowski <m.kozlowski@tuxland.pl> wrote:

> I'm experiencing weird system hangs with recent -mm. After a few hours of uptime for no
> obvious reason system hangs and is (almost) unusable until reset.
>
> a few facts:
>
> - this happens on random basis without anything obvious that could trigger it
> - if some music is played and system hangs the music starts looping in thight loop causing weird
> sound effects
> - sometimes I'm able to switch from X to console, it takes a few seconds to switch though
> - system is eating 100% CPU what is shown by my laptop fans
> - when I switch to console I can issue SysRq commands but they do not work i.e.:
> SysRq + P shows only the first line: "SysRq: Show Regs"
> - in console in which I can log into the system I'm unable to type
> - in console where syslog is logging *.* I'm able to type
> - if the wifi card was plugged into the system before the hang happend the networking seems to work ok
> - when I reattach my pcmcia wifi card it doesn't get detected (nothing happens)
> - when I try to login to my laptop from remote machine the line "login:" and that's it, nothing
> more happens
> - system logs show nothing interesting as even if there is some usable debug info I'm unable to
> SysRq + S and read it after reboot
>
> With 2.6.20-mm1 it happened as well. I get the feeling that 2.6.20-rc2-mm1 needs a bit more uptime
> to hit this bug.

Thanks. Are you sure that the kermel hasn't already oopsed when this
happens? (netconsole will help).

The sysrq-P failure is a shame. Does sysrq-P work as expected _before_ the
system has failed? It sounds to me like a simple log-level thing. Did you
try typing alt-sysrq-7 first?