| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 86/92] s390/mm: Check for valid vma before zapping in gmap_discard | Date | Thu, 29 Nov 2018 15:12:55 +0100 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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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 @@ -686,6 +686,8 @@ 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, NULL); }
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