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authorDavidlohr Bueso <davidlohr@hp.com>2014-04-03 14:47:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-03 16:20:59 -0700
commit7b24d8616be33616efd41ff67d3c76362c60ca84 (patch)
tree6bc0558e36c54f66f73e33a4891e9e5ead924104 /include/linux/hugetlb.h
parent1406ec9ba6c65cb69e9243bff07ca3f51e2525e0 (diff)
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op-kernel-dev-7b24d8616be33616efd41ff67d3c76362c60ca84.tar.gz
mm, hugetlb: fix race in region tracking
There is a race condition if we map a same file on different processes. Region tracking is protected by mmap_sem and hugetlb_instantiation_mutex. When we do mmap, we don't grab a hugetlb_instantiation_mutex, but only mmap_sem (exclusively). This doesn't prevent other tasks from modifying the region structure, so it can be modified by two processes concurrently. To solve this, introduce a spinlock to resv_map and make region manipulation function grab it before they do actual work. [davidlohr@hp.com: updated changelog] Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Suggested-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: David Gibson <david@gibson.dropbear.id.au> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/hugetlb.h')
-rw-r--r--include/linux/hugetlb.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index f62c2f6..5b337cf 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -27,6 +27,7 @@ struct hugepage_subpool {
struct resv_map {
struct kref refs;
+ spinlock_t lock;
struct list_head regions;
};
extern struct resv_map *resv_map_alloc(void);
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