Attachment 299786 Details for Bug 439914 – patch to fix race in alloc_fresh_huge_page

[patch] patch to fix race in alloc_fresh_huge_page

linux-2.6.18-hugetlb-fix-race-in-alloc_fresh_huge_page.patch (text/plain), 1.09 KB, created by Greg Marsden on 2008-03-31 23:07:47 UTC

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Creator: Greg Marsden

Created: 2008-03-31 23:07:47 UTC

Size: 1.09 KB

patch

obsolete

>Subject: hugetlb: fix race in alloc_fresh_huge_page()
>From: Joe Jin <joe.jin@oracle.com>
>
>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>
>---
>--- linux-2.6.18.x86_64/mm/hugetlb.c.orig	2007-08-20 16:48:35.000000000 -0700
>+++ linux-2.6.18.x86_64/mm/hugetlb.c	2007-08-20 16:56:35.000000000 -0700
>@@ -101,13 +101,17 @@
> 
> static int alloc_fresh_huge_page(void)
> {
>-	static int nid = 0;
>+	static int prev_nid = 0;
> 	struct page *page;
>-	page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
>-					HUGETLB_PAGE_ORDER);
>-	nid = next_node(nid, node_online_map);
>+	int nid;
>+	
>+	nid = next_node(prev_nid, node_online_map);
> 	if (nid == MAX_NUMNODES)
> 		nid = first_node(node_online_map);
>+	prev_nid = nid;
>+
>+	page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
>+			           HUGETLB_PAGE_ORDER);
> 	if (page) {
> 		page[1].lru.next = (void *)free_huge_page;	/* dtor */
> 		spin_lock(&hugetlb_lock);

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Attachments on bug 439914: 299786