Re: [PATCH] numa, mem-hotplug: Fix stack overflow in numa whenseting kernel nodes to unhotpluggable.
From: Dave Jones
Date: Thu Jan 23 2014 - 01:14:10 EST
On Wed, Jan 22, 2014 at 10:06:14PM -0800, David Rientjes wrote:
> On Thu, 23 Jan 2014, Tang Chen wrote:
> > Dave found that the kernel will hang during boot. This is because
> > the nodemask_t type stack variable numa_kernel_nodes is large enough
> > to overflow the stack.
> > This doesn't always happen. According to Dave, this happened once
> > in about five boots. The backtrace is like the following:
> > dump_stack
> > panic
> > ? numa_clear_kernel_node_hotplug
> > __stack_chk_fail
> > numa_clear_kernel_node_hotplug
> > ? memblock_search_pfn_nid
> > ? __early_pfn_to_nid
> > numa_init
> > x86_numa_init
> > initmem_init
> > setup_arch
> > start_kernel
> > This patch fix this problem by defining numa_kernel_nodes as a
> > static global variable in __initdata area.
> > Reported-by: Dave Jones <davej@xxxxxxxxxx>
> > Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> > Tested-by: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
> I guess it depends on what Dave's CONFIG_NODES_SHIFT is?
It's 10, because I had MAXSMP set.
So, MAX_NUMNODES = 1 << 10
And the bitmask is made of longs. 1024 of them.
How does this work ?
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