hugetlb: fix race in alloc_fresh_huge_page()
That static `nid' index needs locking. Without it we can end up calling alloc_pages_node() with an illegal node ID and the kernel crashes. Acked-by: gurudas pai <gurudas.pai@oracle.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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15
mm/hugetlb.c
15
mm/hugetlb.c
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@ -101,13 +101,20 @@ static void free_huge_page(struct page *page)
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static int alloc_fresh_huge_page(void)
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{
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static int nid = 0;
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static int prev_nid;
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struct page *page;
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page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
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HUGETLB_PAGE_ORDER);
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nid = next_node(nid, node_online_map);
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static DEFINE_SPINLOCK(nid_lock);
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int nid;
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spin_lock(&nid_lock);
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nid = next_node(prev_nid, node_online_map);
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if (nid == MAX_NUMNODES)
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nid = first_node(node_online_map);
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prev_nid = nid;
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spin_unlock(&nid_lock);
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page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
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HUGETLB_PAGE_ORDER);
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if (page) {
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set_compound_page_dtor(page, free_huge_page);
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spin_lock(&hugetlb_lock);
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