Messages in this thread | | | Date | Wed, 18 Apr 2012 09:58:31 +0400 | From | Konstantin Khlebnikov <> | Subject | Re: [PATCH linux-next] mm/hugetlb: fix warning in alloc_huge_page/dequeue_huge_page_vma |
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Andrew Morton wrote: > On Tue, 17 Apr 2012 16:28:19 +0400 > Konstantin Khlebnikov<khlebnikov@openvz.org> 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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