On Mon, 2014-08-25 at 15:10 +0200, Christian Borntraeger wrote:
> The PFMF instruction handler blindly wrote the storage key even if
> the page was mapped R/O in the host. Lets try a COW before continuing
> and bail out in case of errors.
>
> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> Reviewed-by: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> arch/s390/mm/pgtable.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
> index 19daa53..5404a62 100644
> --- a/arch/s390/mm/pgtable.c
> +++ b/arch/s390/mm/pgtable.c
> @@ -986,11 +986,21 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
> pte_t *ptep;
>
> down_read(&mm->mmap_sem);
> +retry:
> ptep = get_locked_pte(current->mm, addr, &ptl);
> if (unlikely(!ptep)) {
> up_read(&mm->mmap_sem);
> return -EFAULT;
> }
> + if (!(pte_val(*ptep) & _PAGE_INVALID) &&
> + (pte_val(*ptep) & _PAGE_PROTECT)) {
> + pte_unmap_unlock(*ptep, ptl);
> + if (fixup_user_fault(current, mm, addr, FAULT_FLAG_WRITE)) {
> + up_read(&mm->mmap_sem);
> + return -EFAULT;
> + }
> + goto retry;
> + }
Every line below the first 'if' is indented one tab stop too far.
Ben.
> new = old = pgste_get_lock(ptep);
> pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
--
Ben Hutchings
No political challenge can be met by shopping. - George Monbiot
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