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| author | Joe Jin <joe.jin@oracle.com> | 2007-07-15 23:38:12 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-08-09 14:27:40 -0700 |
| commit | 88656e13bea01b02f02a1dfcd3ba75a83e708648 (patch) | |
| tree | 21608b430b40a4777256bf893e07a0ca70e2fc79 | |
| parent | b970e6468dcade5652f0ae02c99189efe1eefec6 (diff) | |
| download | lwn-88656e13bea01b02f02a1dfcd3ba75a83e708648.tar.gz lwn-88656e13bea01b02f02a1dfcd3ba75a83e708648.zip | |
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | mm/hugetlb.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index a45d1f0691ce..5fb38f1c1c37 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -101,13 +101,20 @@ static void free_huge_page(struct page *page) static int alloc_fresh_huge_page(void) { - static int nid = 0; + static int prev_nid; struct page *page; - page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN, - HUGETLB_PAGE_ORDER); - nid = next_node(nid, node_online_map); + static DEFINE_SPINLOCK(nid_lock); + int nid; + + spin_lock(&nid_lock); + nid = next_node(prev_nid, node_online_map); if (nid == MAX_NUMNODES) nid = first_node(node_online_map); + prev_nid = nid; + spin_unlock(&nid_lock); + + page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN, + HUGETLB_PAGE_ORDER); if (page) { set_compound_page_dtor(page, free_huge_page); spin_lock(&hugetlb_lock); |