Messages in this thread | | | Date | Wed, 22 Jan 2014 22:06:14 -0800 (PST) | From | David Rientjes <> | Subject | Re: [PATCH] numa, mem-hotplug: Fix stack overflow in numa when seting kernel nodes to unhotpluggable. |
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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@redhat.com> > Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> > Tested-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
I guess it depends on what Dave's CONFIG_NODES_SHIFT is?
> --- > 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?
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