From: Konrad Rzeszutek Wilk <konrad@kernel.org>
To: xen-devel@lists.xenproject.org, ross.lagerwall@citrix.com,
m.a.young@durham.ac.uk
Subject: Re: Problems with livepatching
Date: Wed, 23 Nov 2016 20:08:36 -0500 [thread overview]
Message-ID: <20161124010837.18077-1-konrad@kernel.org> (raw)
In-Reply-To: <alpine.DEB.2.11.1611240011210.15820@procyon.dur.ac.uk>
On Thu, Nov 24, 2016 at 12:13:43AM +0000, M A Young wrote:
> On Wed, 23 Nov 2016, Andrew Cooper wrote:
>
> > On 23/11/2016 23:06, M A Young wrote:
> > > I have been experimenting with live patching with the recent batch of
> > > security updates on Fedora xen with very limited success. I had most
> > > attempts with a test build of xen-4.8.0-rc6, and of the updates I have
> > > tried only xsa192.patch uploads successfully. For example with
> > > xsa191.patch the upload fails with the output
> > > Uploading /tmp/xen-debuginfo/out1/xsa191.livepatch (1561400 bytes)
> > > Upload failed: /tmp/xen-debuginfo/out1/xsa191.livepatch, error: 2(No such
> > > file or directory)!
> > > and in xl dmesg a long debugging output ends with the line
> > > (XEN) livepatch_elf.c:295: livepatch: xsa191: Unknown symbol: .LC0
> > > with a similar line (mostly with .LC0 but with .LC3 in one case) for the
> > > other failed attempts. Am I doing something wrong or is there a problem
> > > with live patching in this case?
> >
> > This looks like a problem generating the livepatch itself, not the
> > livepatching mechanism.
> >
> > Make sure you are completely up to date with the livepatch tools
> > userspace. There was one bug in livepatch generation which was
> > discovered due to XSA-191 and fixed (actually a preexisting bug even in
> > Linux), but its symptoms were innocuous until you patched, at which vcpu
> > context switch blew up.
>
> Where is this latest version available from? I had checked the git repo on
> xenbits
> http://xenbits.xenproject.org/gitweb/?p=livepatch-build-tools.git;a=summary
> but the last commit was 4 months ago.
Here is the patch that Ross has been working on - it is being first reviewed
for merge in the upstream version of kpatch. Hence hasn't been posted. But
posting it here.
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next prev parent reply other threads:[~2016-11-24 1:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-23 23:06 Problems with livepatching M A Young
2016-11-23 23:35 ` Andrew Cooper
2016-11-24 0:13 ` M A Young
2016-11-24 1:08 ` Konrad Rzeszutek Wilk [this message]
2016-11-24 1:08 ` [PATCH LIVEPATCH-BUILD-TOOLS] create-diff-object: Update fixup offsets in .rela.ex_table Konrad Rzeszutek Wilk
2016-11-24 8:05 ` Ross Lagerwall
2016-11-24 8:52 ` Problems with livepatching Ross Lagerwall
2016-11-24 9:24 ` Lars Kurth
2016-11-24 9:55 ` Ross Lagerwall
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