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authorJanosch Frank <frankja@linux.ibm.com>2018-08-16 11:02:31 +0300
committerJanosch Frank <frankja@linux.ibm.com>2018-09-12 15:46:37 +0300
commit1843abd03250115af6cec0892683e70cf2297c25 (patch)
treeb764158970ec421902e4ad739adac90a3dd42adb /arch/s390/mm
parentdf88f3181f10565c6e3a89eb6f0f9e6afaaf15f1 (diff)
downloadlinux-1843abd03250115af6cec0892683e70cf2297c25.tar.xz
s390/mm: Check for valid vma before zapping in gmap_discard
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>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/gmap.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index bb44990c8212..911c7ded35f1 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -708,11 +708,13 @@ 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;
/*
* We do not discard pages that are backed by
* hugetlbfs, so we don't have to refault them.
*/
- if (vma && is_vm_hugetlb_page(vma))
+ if (is_vm_hugetlb_page(vma))
continue;
size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
zap_page_range(vma, vmaddr, size);