Keir Fraser
2009-Jun-23 10:44 UTC
[Xen-devel] New release candidates for Xen 3.3.2 and 3.4.1
Folks, New release candidates are tagged: http://xenbits.xensource.com/xen-3.3-testing.hg tagged 3.3.2-rc3 http://xenbits.xensource.com/xen-3.4-testing.hg tagged 3.4.1-rc4 Please test! I hope to release later this week. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Frank van der Linden
2009-Jun-23 16:14 UTC
Re: [Xen-devel] New release candidates for Xen 3.3.2 and 3.4.1
Keir Fraser wrote:> Folks, > > New release candidates are tagged: > http://xenbits.xensource.com/xen-3.3-testing.hg tagged 3.3.2-rc3 > http://xenbits.xensource.com/xen-3.4-testing.hg tagged 3.4.1-rc4 > > Please test! I hope to release later this week. > > -- Keir >We are putting our 3.3.2-rc3 based tree through some testing, and are seeing what looks like a shadow page table issue. This issue happens with Solaris (both Solaris 10 and more recent OpenSolaris-based builds), running in a HVM domain. The domain has 3 or more VCPUs (4 is the usual number). At some point, the Solaris kernel will panic. The pattern always looks the same: the Solaris kernel allocates some kmem, and then touches it shortly afterwards (e.g. to zero it out, write a 0xbadcafe debug pattern to it, etc). When it touches the memory, it gets a fatal pagefault (page not present). However, when inspecting the state of the guest page tables, they all look fine. The page is mapped, as far as the guest is concerned. That means that the shadow page table code must have gotten it wrong. An additional data point that points in this direction is that on a system that very reliably reproduces the problem, setting hap=1 makes the problem go away (the problem is reproduced by doing a virt-install, which doesn''t set hap to 1 by default). I''m trying to narrow the circumstances down to get some useful data out of this; I''ll try disabling the out of sync optimizations in the shadow code, etc. I''ve tried to add more instrumentation to the shadow code, but this often changes the timing just enough to avoid the bug. Our code has no changes in the shadow page table code. So far, we haven''t tried to reproduce it on our 3.4-based tree yet (we need a better way to reproduce it in a more controlled environment for that). I''ve filed bug #1480 for this. Oh, and speaking of the out of sync option, Xen doesn''t compile if it''s disabled, because some ifdefs use && instead of &. Patch attached. - Frank _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2009-Jun-23 17:24 UTC
Re: [Xen-devel] New release candidates for Xen 3.3.2 and 3.4.1
On 23/06/2009 17:14, "Frank van der Linden" <Frank.Vanderlinden@Sun.COM> wrote:> We are putting our 3.3.2-rc3 based tree through some testing, and are > seeing what looks like a shadow page table issue.Is this a regression relative to 3.3.1, do you know? That would make it more likely a blocker. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Frank van der Linden
2009-Jun-23 17:43 UTC
Re: [Xen-devel] New release candidates for Xen 3.3.2 and 3.4.1
Keir Fraser wrote:> On 23/06/2009 17:14, "Frank van der Linden" <Frank.Vanderlinden@Sun.COM> > wrote: > > >> We are putting our 3.3.2-rc3 based tree through some testing, and are >> seeing what looks like a shadow page table issue. >> > > Is this a regression relative to 3.3.1, do you know? That would make it more > likely a blocker. > > -- Keir > >I can''t say for sure, unfortunately, since the tests that uncovered this weren''t run on earlier incarnations of our 3.3-based tree. It seems that a few shadow fixes have gone in post 3.3.1, but I have no evidence that these would cause this particular. problem. - Frank _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2009-Jun-23 19:03 UTC
Re: [Xen-devel] New release candidates for Xen 3.3.2 and 3.4.1
On 23/06/2009 18:43, "Frank van der Linden" <Frank.Vanderlinden@Sun.COM> wrote:>> Is this a regression relative to 3.3.1, do you know? That would make it more >> likely a blocker. >> >> -- Keir >> > I can''t say for sure, unfortunately, since the tests that uncovered this > weren''t run on earlier incarnations of our 3.3-based tree. > > It seems that a few shadow fixes have gone in post 3.3.1, but I have no > evidence that these would cause this particular. problem.It might be sensible to try, depending on how long the bug takes to reproduce. If you can be sure that it does not repro with 3.3.1 that has two advantages for you: firstly, I would hold up the 3.3.2 release, and secondly the set of changesets to search for the bug is greatly reduced. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel