On Mon, 2016-11-01 at 15:49:34 UTC, "Aneesh Kumar K.V" wrote: > Core kernel expect swp_entry_t to be consisting of > only swap type and swap offset. We should not leak pte bits to > swp_entry_t. This breaks swapoff which use the swap type and offset > to build a swp_entry_t and later compare that to the swp_entry_t > obtained from linux page table pte. Leaking pte bits to swp_entry_t > breaks that comparison and results in us looping in try_to_unuse. > > The stack trace can be anywhere below try_to_unuse() in mm/swapfile.c, > since swapoff is circling around and around that function, reading from > each used swap block into a page, then trying to find where that page > belongs, looking at every non-file pte of every mm that ever swapped. > > Reported-by: Hugh Dickins <hughd@xxxxxxxxxx> > Suggested-by: Hugh Dickins <hughd@xxxxxxxxxx> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> > Acked-by: Hugh Dickins <hughd@xxxxxxxxxx> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/44734f23de2465c3c0d39e4a16 cheers -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>