Re: [PATCH 6.1] KVM: x86/mmu: Fix an sign-extension bug with mmu_seq that hangs vCPUs

From: Sean Christopherson
Date: Thu Aug 24 2023 - 09:48:06 EST


On Thu, Aug 24, 2023, Greg Kroah-Hartman wrote:
> On Wed, Aug 23, 2023 at 06:01:04PM -0700, Sean Christopherson wrote:
> > Note, upstream commit ba6e3fe25543 ("KVM: x86/mmu: Grab mmu_invalidate_seq
> > in kvm_faultin_pfn()") unknowingly fixed the bug in v6.3 when refactoring
> > how KVM tracks the sequence counter snapshot.
> >
> > Reported-by: Brian Rak <brak@xxxxxxxxx>
> > Reported-by: Amaan Cheval <amaan.cheval@xxxxxxxxx>
> > Reported-by: Eric Wheeler <kvm@xxxxxxxxxxxxxxxxxx>
> > Closes: https://lore.kernel.org/all/f023d927-52aa-7e08-2ee5-59a2fbc65953@xxxxxxxxxxxxxxx
> > Fixes: a955cad84cda ("KVM: x86/mmu: Retry page fault if root is invalidated by memslot update")
> > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> What is the git commit id of this change in Linus's tree?

There is none. Commit ba6e3fe25543 (landed in v6.3) unknowingly fixed the bug as
part of a completely unrelated refactoring.