On Tue, 11 Apr 2017 22:31:12 +0100 Colin Ian King <[email protected]> wrote:
> On 11/04/17 22:26, Andrew Morton wrote: > > On Tue, 11 Apr 2017 13:51:02 +0100 Colin King <[email protected]> > > wrote: > > > >> From: Colin Ian King <[email protected]> > >> > >> check if vma is null before dereferencing it, this avoiding any > >> potential null pointer dereferences on vma via the is_vm_hugetlb_page > >> call or the direct vma->vm_flags reference. > >> > >> Detected with CoverityScan, CID#1427995 ("Dereference before null check") > >> > >> ... > >> > >> --- a/mm/migrate.c > >> +++ b/mm/migrate.c > >> @@ -2757,10 +2757,10 @@ int migrate_vma(const struct migrate_vma_ops *ops, > >> /* Sanity check the arguments */ > >> start &= PAGE_MASK; > >> end &= PAGE_MASK; > >> - if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) > >> - return -EINVAL; > >> if (!vma || !ops || !src || !dst || start >= end) > >> return -EINVAL; > >> + if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) > >> + return -EINVAL; > >> if (start < vma->vm_start || start >= vma->vm_end) > >> return -EINVAL; > >> if (end <= vma->vm_start || end > vma->vm_end) > > > > I don't know what kernel version this is against but I don't think it's > > anything recent? > > I should have said it was against linux-next ah, it modifies an HMM patch which I dropped a couple of hours ago. One for Jerome, please.
