The patch titled
hugetlb: fix race in alloc_fresh_huge_page()
has been added to the -mm tree. Its filename is
hugetlb-fix-race-in-alloc_fresh_huge_page.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: hugetlb: fix race in alloc_fresh_huge_page()
From: Joe Jin <joe.jin@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 15 +++++++++++----
1 files changed, 11 insertions(+), 4 deletions(-)
diff -puN mm/hugetlb.c~hugetlb-fix-race-in-alloc_fresh_huge_page mm/hugetlb.c
--- a/mm/hugetlb.c~hugetlb-fix-race-in-alloc_fresh_huge_page
+++ a/mm/hugetlb.c
@@ -101,13 +101,20 @@ static void free_huge_page(struct 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);
_
Patches currently in -mm which might be from joe.jin@xxxxxxxxxx are
hugetlb-fix-race-in-alloc_fresh_huge_page.patch
-
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