In the Linux kernel, the following vulnerability has been resolved:

nommu: pass NULL argument to vma_iter_prealloc()

When deleting a vma entry from a maple tree, it has to pass NULL to
vma_iter_prealloc() in order to calculate internal state of the tree, but
it passed a wrong argument.  As a result, nommu kernels crashed upon
accessing a vma iterator, such as acct_collect() reading the size of vma
entries after do_munmap().

This commit fixes this issue by passing a right argument to the
preallocation call.