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| author |   David Hildenbrand <david@redhat.com> | 2021-09-09 18:22:41 +0200 |
|---|---|---|
| committer |   Christian Borntraeger <borntraeger@de.ibm.com> | 2021-10-25 09:20:38 +0200 |
| commit | b159f94c86b43cf7e73e654bc527255b1f4eafc4 (patch) | |
| tree | 2c25f796861da3dc1c2f18038edb32b623ea4af3 /arch/s390 | |
| parent | s390/gmap: validate VMA in __gmap_zap() (diff) | |
| download | linux-dev-b159f94c86b43cf7e73e654bc527255b1f4eafc4.tar.xz linux-dev-b159f94c86b43cf7e73e654bc527255b1f4eafc4.zip | |
s390/gmap: don't unconditionally call pte_unmap_unlock() in __gmap_zap()
... otherwise we will try unlocking a spinlock that was never locked via a
garbage pointer.
At the time we reach this code path, we usually successfully looked up
a PGSTE already; however, evil user space could have manipulated the VMA
layout in the meantime and triggered removal of the page table.
Fixes: 1e133ab296f3 ("s390/mm: split arch/s390/mm/pgtable.c")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20210909162248.14969-3-david@redhat.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/mm/gmap.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index e0735c343775..d63c0ccc5ccd 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -689,9 +689,10 @@ void __gmap_zap(struct gmap *gmap, unsigned long gaddr) /* Get pointer to the page table entry */ ptep = get_locked_pte(gmap->mm, vmaddr, &ptl); - if (likely(ptep)) + if (likely(ptep)) { ptep_zap_unused(gmap->mm, vmaddr, ptep, 0); - pte_unmap_unlock(ptep, ptl); + pte_unmap_unlock(ptep, ptl); + } } } EXPORT_SYMBOL_GPL(__gmap_zap); |