Messages in this thread | | | Date | Wed, 28 Apr 2010 11:50:39 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] Fix NULL pointer for Xen guests |
| |
On Wed, 28 Apr 2010 14:29:06 -0400 Prarit Bhargava <prarit@redhat.com> wrote:
> > > On 04/28/2010 02:26 PM, Andrew Morton wrote: > > On Tue, 27 Apr 2010 11:24:42 -0400 > > Prarit Bhargava<prarit@redhat.com> wrote: > > > > > >> Upstream PV guests fail to boot because of a NULL pointer. It is possible that > >> xen guests have irq_desc->chip_data = NULL. > >> > >> Test for NULL chip_data pointer before attempting to complete an irq move. > >> > >> Signed-off-by: Prarit Bhargava<prarit@redhat.com> > >> Acked-by: Suresh Siddha<suresh.b.siddha@intel.com> > >> > >> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c > >> index 127b871..eb2789c 100644 > >> --- a/arch/x86/kernel/apic/io_apic.c > >> +++ b/arch/x86/kernel/apic/io_apic.c > >> @@ -2545,6 +2545,9 @@ void irq_force_complete_move(int irq) > >> struct irq_desc *desc = irq_to_desc(irq); > >> struct irq_cfg *cfg = desc->chip_data; > >> > >> + if (!cfg) > >> + return; > >> + > >> __irq_complete_move(&desc, cfg->vector); > >> } > >> #else > >> > > I assume this is needed for 2.6.34? > > > > What about 2.6.33.x and earlier? > > > > Hey Andrew, > > I actually pinged Chris Wright to see about including this in the > -stable branches. I haven't heard anything back so I'll reping him. >
Well. Pinging people offlist isn't very reliable. Put
Cc: <stable@kernel.org>
at the end of the changelog and cc stable@kernel.org on the original patch and then the patch will reliably receive consideration for backporting.
I have added Cc:<stable@kernel.org> to my copy of the patch, so the -stable guys will at least see it when I drop it after it is merged. But if the x86 maintainers were to merge your patch as you sent it, it would have no Cc: <stable@kernel.org> when it goes into Linus's tree.
I worry that if the -stable maintainer see me drop a patch, but the patch in Linus's tree doesn't have the stable tag, they might not merge the fix into -stable. I bugged them about this scenario recently and the reply was a bit waffly ;)
By far the safest thing to do is to include the stable tag in your changelog right at the outset.
| |