Andrew Morton wrote:
On Tue, 17 Apr 2012 16:28:19 +0400 Konstantin Khlebnikov<khlebnikov@xxxxxxxxxx> wrote:This patch fixes gcc warning (and bug?) introduced in linux-next commit cc9a6c877 ("cpuset: mm: reduce large amounts of memory barrier related damage v3") Local variable "page" can be uninitialized if nodemask from vma policy does not intersects with nodemask from cpuset. Even if it wouldn't happens it's better to initialize this variable explicitly than to introduce kernel oops on 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 ... --- 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;hm, that's a pretty blatant use-uninitialised bug. I wonder why so few gcc versions report it. Mine doesn't.
I'm using latest gcc-4.7
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