Messages in this thread | | | Date | Tue, 28 Jan 2014 10:24:57 -0500 | From | Dave Jones <> | Subject | Re: [PATCH 2/2] numa, mem-hotplug: Fix array index overflow when synchronizing nid to memblock.reserved. |
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On Tue, Jan 28, 2014 at 05:05:16PM +0800, Tang Chen wrote: > The following path will cause array out of bound. > > memblock_add_region() will always set nid in memblock.reserved to MAX_NUMNODES. > In numa_register_memblks(), after we set all nid to correct valus in memblock.reserved, > we called setup_node_data(), and used memblock_alloc_nid() to allocate memory, with > nid set to MAX_NUMNODES. > > The nodemask_t type can be seen as a bit array. And the index is 0 ~ MAX_NUMNODES-1. > > After that, when we call node_set() in numa_clear_kernel_node_hotplug(), the nodemask_t > got an index of value MAX_NUMNODES, which is out of [0 ~ MAX_NUMNODES-1]. > > See below: > > numa_init() > |---> numa_register_memblks() > | |---> memblock_set_node(memory) set correct nid in memblock.memory > | |---> memblock_set_node(reserved) set correct nid in memblock.reserved > | |...... > | |---> setup_node_data() > | |---> memblock_alloc_nid() here, nid is set to MAX_NUMNODES (1024) > |...... > |---> numa_clear_kernel_node_hotplug() > |---> node_set() here, we have an index 1024, and overflowed > > This patch moves nid setting to numa_clear_kernel_node_hotplug() to fix this problem. > > 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> > --- > arch/x86/mm/numa.c | 19 +++++++++++-------- > 1 file changed, 11 insertions(+), 8 deletions(-)
This does seem to solve the problem (In conjunction with David's variant of the other patch).
Dave
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