mmap: check ->vm_ops before dereferencing

Check whether the VMA has a vm_ops before calling close, just
like we check vm_ops before calling open a few dozen lines
higher up in the function.

Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index f90ea92f755aed2a9d7fa8dac940443dd86240f8..456ec6f278897a560bd915e6d84297ac3de7ddef 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1977,7 +1977,8 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
                return 0;
 
        /* Clean everything up if vma_adjust failed. */
-       new->vm_ops->close(new);
+       if (new->vm_ops && new->vm_ops->close)
+               new->vm_ops->close(new);
        if (new->vm_file) {
                if (vma->vm_flags & VM_EXECUTABLE)
                        removed_exe_file_vma(mm);