Re: [PATCH] xen: fix logical error in tlb flushing

Konrad Rzeszutek Wilk
2012-08-24T18:20:18Z

On Fri, Aug 24, 2012 at 04:16:39PM +0100, Jan Beulich wrote:
> >>> On 24.08.12 at 10:55, Alex Shi <alex.shi@intel.com> wrote:
> > While TLB_FLUSH_ALL gets passed as 'end' argument to
> > flush_tlb_others(), the Xen code was made to check its 'start'
> > parameter. That may give a incorrect op.cmd to MMUEXT_INVLPG_MULTI
> > instead of MMUEXT_TLB_FLUSH_MULTI. Then it causes some page can not
> > be flushed from TLB.
> >
> > This patch fixed this issue.
> >
> > Reported-by: Jan Beulich <jbeulich@suse.com>
> > Signed-off-by: Alex Shi <alex.shi@intel.com>
>
> Acked-by: Jan Beulich <jbeulich@suse.com>

How can I reproduce this and should this also go to stable@kernel.org?
>
> > ---
> > arch/x86/xen/mmu.c | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> > index b65a761..5141d80 100644
> > --- a/arch/x86/xen/mmu.c
> > +++ b/arch/x86/xen/mmu.c
> > @@ -1283,7 +1283,7 @@ static void xen_flush_tlb_others(const struct cpumask
> > *cpus,
> > cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
> >
> > args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
> > - if (start != TLB_FLUSH_ALL && (end - start) <= PAGE_SIZE) {
> > + if (end != TLB_FLUSH_ALL && (end - start) <= PAGE_SIZE) {
> > args->op.cmd = MMUEXT_INVLPG_MULTI;
> > args->op.arg1.linear_addr = start;
> > }
> > --
> > 1.7.5.4
> >
> > .
>
>
>