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powerpc/booke: Only check for hugetlb in flush if vma != NULL 

And in flush_hugetlb_page(), don't check whether vma is NULL after
we've already dereferenced it.

This was found by Dan using static analysis as described here:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2013-November/113161.html

We currently get away with this because the callers that currently pass
NULL for vma seem to be 32-bit-only (e.g. highmem, and
CONFIG_DEBUG_PGALLOC in pgtable_32.c)  Hugetlb is currently 64-bit only,
so we never saw a NULL vma here.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
This commit is contained in:
Scott Wood 2013-11-21 18:26:42 -06:00
parent 53567cf3c2
commit d742aa152f
2 changed files with 2 additions and 3 deletions
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3
arch/powerpc/mm/hugetlbpage-book3e.c
View File

@ -117,6 +117,5 @@ void flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
struct hstate *hstate = hstate_file(vma->vm_file);
unsigned long tsize = huge_page_shift(hstate) - 10;
__flush_tlb_page(vma ? vma->vm_mm : NULL, vmaddr, tsize, 0);
__flush_tlb_page(vma->vm_mm, vmaddr, tsize, 0);
}

2
arch/powerpc/mm/tlb_nohash.c
View File

@ -305,7 +305,7 @@ void __flush_tlb_page(struct mm_struct *mm, unsigned long vmaddr,
void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
{
#ifdef CONFIG_HUGETLB_PAGE
if (is_vm_hugetlb_page(vma))
if (vma && is_vm_hugetlb_page(vma))
flush_hugetlb_page(vma, vmaddr);
#endif