Re: [PATCH] numa, mem-hotplug: Fix stack overflow in numa when setingkernel nodes to unhotpluggable.

From: David Rientjes
Date: Mon Jan 27 2014 - 19:33:10 EST


On Wed, 22 Jan 2014, David Rientjes wrote:

> > arch/x86/mm/numa.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> > index 81b2750..ebefeb7 100644
> > --- a/arch/x86/mm/numa.c
> > +++ b/arch/x86/mm/numa.c
> > @@ -562,10 +562,10 @@ static void __init numa_init_array(void)
> > }
> > }
> >
> > +static nodemask_t numa_kernel_nodes __initdata;
> > static void __init numa_clear_kernel_node_hotplug(void)
> > {
> > int i, nid;
> > - nodemask_t numa_kernel_nodes;
> > unsigned long start, end;
> > struct memblock_type *type = &memblock.reserved;
> >
>
> Isn't this also a bugfix since you never initialize numa_kernel_nodes when
> it's allocated on the stack with NODE_MASK_NONE?
>

This hasn't been answered and the patch still isn't in linux-kernel yet
Dave tested it as good. I'm suspicious of the changelog that indicates
this nodemask is the result of a stack overflow itself which only manages
to reproduce itself in the init patch slightly more than 50% of the time.
How is that possible?

I think the changelog should indicate this also fixes an uninitialized
nodemask issue.
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