On 10/16/2014 11:31 AM, Don Dutile wrote: > On 10/16/2014 05:45 AM, Christoffer Dall wrote: >> Hi Joel, >> >> On Wed, Oct 08, 2014 at 04:54:31PM +0200, Christoffer Dall wrote: >>> On Wed, Oct 08, 2014 at 09:14:09AM -0500, Joel Schopp wrote: >>>> >>>>>> Traced it back to the introduction of NO_HZ. Going from >>>>>> CONFIG_HZ_PERIODIC to CONFIG_NO_HZ_IDLE or CONFIG_NO_HZ_FULL is >>>>>> enough >>>>>> to do it. >>>>> Is this specific to running in a VM or do those options break your >>>>> host >>>>> system as well? >>>> Just the guest. The same kernel boots on the host. >>>> >>> That's concerning.... We could be losing interrupts for some reason. >>> >> I tried to reproduce this and I really cannot reproduce it. >> >> I talked to Don Dutile from Red Hat yesterday, and he said he had seen >> the same behavior when configuring the NO_HZ incorrectly, something >> about the clocksources getting confused and the system times out before >> loading the libararies, producing the behavior you're seeing. >> >> Are you setting these options with menuconfig or manually in the .config >> file? >> >> It owuld be interesting if you could do a blank defconfig and enable the >> NO_HZ options through a menuconfig and see if you can reproduce that >> way? >> >> Thanks, >> -Christoffer >> > Here are my (working) timer config options: > # > # Timers subsystem > # > CONFIG_TICK_ONESHOT=y > CONFIG_NO_HZ_COMMON=y > # CONFIG_HZ_PERIODIC is not set > CONFIG_NO_HZ_IDLE=y > # CONFIG_NO_HZ_FULL is not set > CONFIG_NO_HZ=y > CONFIG_HIGH_RES_TIMERS=y > > > If I recall correctly, having NO_HZ_FULL set to y > is what broke my kernel with similar stack trace that Christoffer > showed me yesterday. > > hope that helps. Started taking a look at 3.18-rc2. It seems that this problem is worse now. In the previous version I was able to make the problem go away in the guest by disabling NO_HZ_FULL. Now no combination of build options will boot the guest, it always dies in init. I also cannot boot the host anymore, the host also dies in init with the same problem (either too short shared library file or trying to access 0). _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
