BUG: soft lockup - CPU stuck for ...
Hi,
many thanks for your replys. I've upgraded some systems to kernel 2.6.29 a few days ago. There was especially one system which nearly always crashed during kernel compilation. With 2.6.29 as host an guest it currently works. Have now compiled the kernel three times (always from scratch) and nothing crashed.
To use i686 (or x86) as host wouldn't be a option.
The preemtible kernel seems a possible way to go if the crash happens again. But if it works now I'll leave it as it is since there are still drivers out there which have problems with preemt. kernels.
But there is something I still wonder: Is this the right mailing list for such requests? If I read a message like "BUG: soft lockup - CPU#0 stuck for ..."? it looks for me like a bug which should be looked after by the develpers but it seems that nobody here really cares for such reports. I'm really a gratefull for KVM and the work by done by all the developers but isn't it in the interest of a company like Redhat to get the product stable and to eliminate all known bugs before the release of their new virtualisation product? I really don't mean this as flame because my intention is really to get KVM better. But the only thing I can do is to submit bug reports since I'm not a C/C++ developer.
Btw: Is there a overview what kernel settings are recommended for KVM hosts and guests beside the obvious ones? I've learned so far that the noop I/O scheduler in the guest and deadline in the host are good choices. I've read in the XFS filesystem FAQ that the KVM "drive=" option should include "cache=none" to avoid filesystem corruption (which I've already had in some KVMs and caused me to switch to ext3 instead). The kernel settings are especially usefull for people like me who're using Gentoo where you have to compile everything yourself.
Keep the good work going!
Thanks!
Robert
many than
Quoted 8 lines
Hi,
I was also experiencing this problem a lot for quite a long time (and for wide range of KVM versions..)
I might be completely wrong as I'm not sure if it was really the reason, but i THINK it disappeared when I started to use fully preemptible kernel on host.. You might want to try it...
BR
nik
Quoted 36 lines · Gerrit Slomma
Quoted 12 lines · Robert Wimmer <r.wimmer <at> tomorrow-focus.de> writes:
Hi,
does anyone know how to solve the problem
with "BUG: soft lockup - CPU#0 stuck for ..."?
Today I got the messages below during compilation
of the kernel modules in a guest. Using kvm84 and Kernel 2.6.29 as host kernel and 2.6.28 as guest kernel during the hangup of the guest neither ssh or ping was possible. After about 2 minutes the guest was reachable again and I saw the messages below with "dmesg".Quoted 8 lines
Maybe it is related with my prev. anserwed posting:
http://article.gmane.org/gmane.comp.emulators.kvm.devel/29677Thanks!
RobertBUG: soft lockup - CPU#0 stuck for 61s!(...)
Hello
Do you use
x86_64or i686?
Look at my post here http://article.gmane.org/gmane.comp.emulators.kvm.devel/29833
And my Bug-report here https://bugzilla.redhat.com/show_bug.cgi?id=492688.
I do not have the problems while running but after migrating. Problems with stuck CPUs vanish if i686 for the host is used - but i am testing further.--
To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo <at> vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Signature · 18 lines
------------------------------------- Nikola CIPRICH LinuxBox.cz, s.r.o. 28. rijna 168, 709 01 Ostrava tel.: +420 596 603 142 fax: +420 596 621 273 mobil: +420 777 093 799 www.linuxbox.cz <http://www.linuxbox.cz> mobil servis: +420 737 238 656 email servis: servis <at> linuxbox.cz ------------------------------------- -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo <at> vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Quoted 17 lines · On Monday 30 March 2009 06:37:35 Robert Wimmer wrote:
Hi,
many thanks for your replys. I've upgraded some systems to kernel 2.6.29 a few days ago. There was especially one system which nearly always crashed during kernel compilation. With 2.6.29 as host an guest it currently works. Have now compiled the kernel three times (always from scratch) and nothing crashed.
To use i686 (or x86) as host wouldn't be a option.
The preemtible kernel seems a possible way to go if the crash happens again. But if it works now I'll leave it as it is since there are still drivers out there which have problems with preemt. kernels.
Quoted 14 lines
But there is something I still wonder: Is this the right mailing list for such requests? If I read a message like "BUG: soft lockup - CPU#0 stuck for ..."? it looks for me like a bug which should be looked after by the develpers but it seems that nobody here really cares for such reports. I'm really a gratefull for KVM and the work by done by all the developers but isn't it in the interest of a company like Redhat to get the product stable and to eliminate all known bugs before the release of their new virtualisation product? I really don't mean this as flame because my intention is really to get KVM better. But the only thing I can do is to submit bug reports since I'm not a C/C++ developer.
I think your problem is timing. All the devs seem to be really focused on getting kvm merged into upstream qemu properly right now. Following the list I've noticed that at least one of the devs seems to do a weekly review of the list and tries to handle all the bugs he sees. I actually think filing bugs for bugs is probably a better way to go because it's easier for the devs to keep track of them there (rather than having to read through a ton of mailing list messages, some of which don't even have to do with kvm). Moral of the story... even though nobody replied to you (yet?) your reports and time spent finding workarounds is appreciated.
Quoted 67 lines
Btw: Is there a overview what kernel settings are recommended for KVM hosts and guests beside the obvious ones? I've learned so far that the noop I/O scheduler in the guest and deadline in the host are good choices. I've read in the XFS filesystem FAQ that the KVM "drive=" option should include "cache=none" to avoid filesystem corruption (which I've already had in some KVMs and caused me to switch to ext3 instead). The kernel settings are especially usefull for people like me who're using Gentoo where you have to compile everything yourself.
Keep the good work going!
Thanks!
Robertmany than
Quoted 8 lines
Hi,
I was also experiencing this problem a lot for quite a long time (and for wide range of KVM versions..)
I might be completely wrong as I'm not sure if it was really the reason, but i THINK it disappeared when I started to use fully preemptible kernel on host.. You might want to try it...
BR
nikQuoted 35 lines · Gerrit Slomma
Quoted 11 lines · Robert Wimmer <r.wimmer <at> tomorrow-focus.de> writes:
Hi,
does anyone know how to solve the problem
with "BUG: soft lockup - CPU#0 stuck for ..."?
Today I got the messages below during compilation
of the kernel modules in a guest. Using kvm84 and Kernel 2.6.29 as host kernel and 2.6.28 as guest kernel during the hangup of the guest neither ssh or ping was possible. After about 2 minutes the guest was reachable again and I saw the messages below with "dmesg".Quoted 8 lines
Maybe it is related with my prev. anserwed posting:
http://article.gmane.org/gmane.comp.emulators.kvm.devel/29677Thanks!
RobertBUG: soft lockup - CPU#0 stuck for 61s!(...)
Hello
Do you use
x86_64or i686?
Look at my post here
http://article.gmane.org/gmane.comp.emulators.kvm.devel/29833 And my Bug-report here https://bugzilla.redhat.com/show_bug.cgi?id=492688. I do not have the problems while running but after migrating. Problems with stuck CPUs vanish if i686 for the host is used - but i am testing further.--
To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo <at> vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html