From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Janosch Frank , David Hildenbrand , Dan Carpenter 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 Message-Id: <20181129140113.671722395@linuxfoundation.org> In-Reply-To: <20181129140106.520639693@linuxfoundation.org> References: <20181129140106.520639693@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Janosch Frank 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(+) --- 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); }