From b1c12cbcd0a02527c180a862e8971e249d3b347d Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Wed, 25 Apr 2012 16:01:46 -0700 Subject: mm/hugetlb: fix warning in alloc_huge_page/dequeue_huge_page_vma Fix a gcc warning (and bug?) introduced in cc9a6c877 ("cpuset: mm: reduce large amounts of memory barrier related damage v3") Local variable "page" can be uninitialized if the nodemask from vma policy does not intersects with nodemask from cpuset. Even if it doesn't happens it is better to initialize this variable explicitly than to introduce a kernel oops in a weird corner case. mm/hugetlb.c: In function `alloc_huge_page': mm/hugetlb.c:1135:5: warning: `page' may be used uninitialized in this function Signed-off-by: Konstantin Khlebnikov Acked-by: Mel Gorman Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/hugetlb.c') diff --git a/mm/hugetlb.c b/mm/hugetlb.c index cd65cb19c941..5a16423a512c 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -532,7 +532,7 @@ static struct page *dequeue_huge_page_vma(struct hstate *h, struct vm_area_struct *vma, unsigned long address, int avoid_reserve) { - struct page *page; + struct page *page = NULL; struct mempolicy *mpol; nodemask_t *nodemask; struct zonelist *zonelist; -- cgit v1.2.2 From 4998a6c0edce7fae9c0a5463f6ec3fa585258ee7 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Thu, 10 May 2012 13:01:44 -0700 Subject: hugetlb: prevent BUG_ON in hugetlb_fault() -> hugetlb_cow() Commit 66aebce747eaf ("hugetlb: fix race condition in hugetlb_fault()") added code to avoid a race condition by elevating the page refcount in hugetlb_fault() while calling hugetlb_cow(). However, one code path in hugetlb_cow() includes an assertion that the page count is 1, whereas it may now also have the value 2 in this path. The consensus is that this BUG_ON has served its purpose, so rather than extending it to cover both cases, we just remove it. Signed-off-by: Chris Metcalf Acked-by: Mel Gorman Acked-by: Hillf Danton Acked-by: Hugh Dickins Cc: Michal Hocko Cc: KAMEZAWA Hiroyuki Cc: [3.0.29+, 3.2.16+, 3.3.3+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 1 - 1 file changed, 1 deletion(-) (limited to 'mm/hugetlb.c') diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 5a16423a512c..ae8f708e3d75 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2498,7 +2498,6 @@ retry_avoidcopy: if (outside_reserve) { BUG_ON(huge_pte_none(pte)); if (unmap_ref_private(mm, vma, old_page, address)) { - BUG_ON(page_count(old_page) != 1); BUG_ON(huge_pte_none(pte)); spin_lock(&mm->page_table_lock); ptep = huge_pte_offset(mm, address & huge_page_mask(h)); -- cgit v1.2.2