tree ad6d608b560dc540330bdcc89e8702ac85993174
parent 2ebe31513fcbe7a781f27002f065b50ae195022f
author David Woodhouse <David.Woodhouse@intel.com> 1253370988 -0700
committer David Woodhouse <David.Woodhouse@intel.com> 1253370988 -0700

intel-iommu: Fix integer overflow in dma_pte_{clear_range,free_pagetable}()

If end_pfn is equal to (unsigned long)-1, then the loop will never end.

Seen on 32-bit kernel, but could have happened on 64-bit too once we get
hardware that supports 64-bit guest addresses.

Change both functions to a 'do {} while' loop with the test at the end,
and check for the PFN having wrapper round to zero.

Reported-by: Benjamin LaHaise <ben.lahaise@neterion.com>
Tested-by: Benjamin LaHaise <ben.lahaise@neterion.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>