From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Linux Next Mailing List <linux-next@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
KVM <kvm@vger.kernel.org>, Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Subject: Re: linux-next: Tree for Mar 25 (arch/x86/kvm/)
Date: Wed, 25 Mar 2020 11:47:41 -0700 [thread overview]
Message-ID: <20200325184741.GI14294@linux.intel.com> (raw)
In-Reply-To: <20200325164606.GH14294@linux.intel.com>
On Wed, Mar 25, 2020 at 09:46:06AM -0700, Sean Christopherson wrote:
> On Wed, Mar 25, 2020 at 05:26:20PM +0100, Paolo Bonzini wrote:
> > On 25/03/20 17:14, Sean Christopherson wrote:
> > >> Doh, right. I think the only solution for that one is to degrade it to
> > >> WARN_ON(1).
> > > I reproduced the error, give me a bit to play with the code to see if the
> > > BUILD_BUG can be preserved. I'm curious as to why kvm_cpu_cap_mask() is
> > > special, and why it only fails with this config.
> > >
> >
> > I could not reproduce it, but I would not be surprised if there are
> > other configurations where the compiler cannot constant-propagate from
> > the reverse_cpuid struct into __cpuid_entry_get_reg.
>
> The error is related to UBSAN. There is at least one legitimate (but benign)
> underlying issue. I'm chasing down a second instance of the BUILD_BUG.
Argh, red herring. There is no underlying issue other than gcc tripping up
when -fsanitize=alignment is enabled by UBSAN. Good news is that the build
error can be fixed without resorting to a hack.
prev parent reply other threads:[~2020-03-25 18:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 8:53 linux-next: Tree for Mar 25 Stephen Rothwell
2020-03-25 15:30 ` linux-next: Tree for Mar 25 (arch/x86/kvm/) Randy Dunlap
2020-03-25 15:32 ` Sean Christopherson
2020-03-25 15:46 ` Paolo Bonzini
2020-03-25 15:57 ` Randy Dunlap
2020-03-25 16:08 ` Paolo Bonzini
2020-03-25 16:14 ` Sean Christopherson
2020-03-25 16:26 ` Paolo Bonzini
2020-03-25 16:46 ` Sean Christopherson
2020-03-25 18:47 ` Sean Christopherson [this message]
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