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s390/mm: missing pte for gmap_ipte_notify should trigger a VM_BUG 

After fixup_user_fault does not fail we have a writeable pte.
That pte might transform but it should not vanish.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
hifive-unleashed-5.1
Dominik Dingel 2014-10-15 15:29:01 +02:00 committed by Martin Schwidefsky
parent 7a5388de5c
commit 6972cae523
1 changed files with 1 additions and 2 deletions
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3
arch/s390/mm/pgtable.c
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@ -752,8 +752,7 @@ int gmap_ipte_notify(struct gmap *gmap, unsigned long gaddr, unsigned long len)
break;
/* Walk the process page table, lock and get pte pointer */
ptep = get_locked_pte(gmap->mm, addr, &ptl);
if (unlikely(!ptep))
continue;
VM_BUG_ON(!ptep);
/* Set notification bit in the pgste of the pte */
entry = *ptep;
if ((pte_val(entry) & (_PAGE_INVALID | _PAGE_PROTECT)) == 0) {