From aef9f7db7e8cf0cd5357e5b449669af1e7cdccad Mon Sep 17 00:00:00 2001 From: Janosch Frank Date: Thu, 16 Aug 2018 09:02:31 +0100 Subject: s390/mm: Check for valid vma before zapping in gmap_discard 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 Reviewed-by: David Hildenbrand Reported-by: Dan Carpenter Message-Id: <20180816082432.78828-1-frankja@linux.ibm.com> Signed-off-by: Janosch Frank Signed-off-by: Greg Kroah-Hartman --- arch/s390/mm/gmap.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/s390') diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 2f66290c9b92..ec9292917d3f 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -689,6 +689,8 @@ void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to) 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); } -- cgit v1.2.3