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| author |   Janosch Frank <frankja@linux.ibm.com> | 2018-08-16 09:02:31 +0100 |
|---|---|---|
| committer | Janosch Frank <frankja@linux.ibm.com> | 2018-09-12 14:46:37 +0200 |
| commit | 1843abd03250115af6cec0892683e70cf2297c25 (patch) | |
| tree | b764158970ec421902e4ad739adac90a3dd42adb /arch/s390/mm/gmap.c | |
| parent | KVM: s390: Properly lock mm context allow_gmap_hpage_1m setting (diff) | |
| download | linux-dev-1843abd03250115af6cec0892683e70cf2297c25.tar.xz linux-dev-1843abd03250115af6cec0892683e70cf2297c25.zip | |
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/gmap.c')
| -rw-r--r-- | arch/s390/mm/gmap.c | 4 |
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); |