Libin wrote: > find_vma may return NULL, thus check the return > value to avoid NULL pointer dereference. > > Signed-off-by: Libin <huawei.libin@xxxxxxxxxx> Looks correct to me. Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Have you ever triggered the race or just found it by reading the code? I wounder if it's subject for stable@. > --- > mm/huge_memory.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 243e710..d4423f4 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2294,6 +2294,8 @@ static void collapse_huge_page(struct mm_struct *mm, > goto out; > > vma = find_vma(mm, address); > + if (!vma) > + goto out; > hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; > hend = vma->vm_end & HPAGE_PMD_MASK; > if (address < hstart || address + HPAGE_PMD_SIZE > hend) > -- > 1.8.2.1 -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>