4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Janosch Frank frankja@linux.ibm.com
commit 1843abd03250115af6cec0892683e70cf2297c25 upstream.
Userspace could have munmapped the area before doing unmapping from the gmap. This would leave us with a valid vmaddr, but an invalid vma from which we would try to zap memory.
Let's check before using the vma.
Fixes: 1e133ab296f3 ("s390/mm: split arch/s390/mm/pgtable.c") Signed-off-by: Janosch Frank frankja@linux.ibm.com Reviewed-by: David Hildenbrand david@redhat.com Reported-by: Dan Carpenter dan.carpenter@oracle.com Message-Id: 20180816082432.78828-1-frankja@linux.ibm.com Signed-off-by: Janosch Frank frankja@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/mm/gmap.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -689,6 +689,8 @@ void gmap_discard(struct gmap *gmap, uns vmaddr |= gaddr & ~PMD_MASK; /* Find vma in the parent mm */ vma = find_vma(gmap->mm, vmaddr); + if (!vma) + continue; size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK)); zap_page_range(vma, vmaddr, size); }