Re: [PATCH 8/8] vrange: Send SIGBUS when user try to access purgedpage

[Minchan Kim]

On Tue, Jun 11, 2013 at 09:22:51PM -0700, John Stultz wrote:
> From: Minchan Kim <minchan@xxxxxxxxxx>
> 
> By vrange(2) semantic, user should see SIGBUG if he try to access
> purged page without vrange(...VRANGE_NOVOLATILE).
> 
> This patch implements it.
> 
> XXX: I reused PSE bit for quick prototype without enough considering
> so need time to see what's empty bit and I am surely missing
> many places to handle vrange pte bit. I should investigate all of
> pte handling places, especially pte_none case.
> 
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Android Kernel Team <kernel-team@xxxxxxxxxxx>
> Cc: Robert Love <rlove@xxxxxxxxxx>
> Cc: Mel Gorman <mel@xxxxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
> Cc: Rik van Riel <riel@xxxxxxxxxx>
> Cc: Dmitry Adamushko <dmitry.adamushko@xxxxxxxxx>
> Cc: Dave Chinner <david@xxxxxxxxxxxxx>
> Cc: Neil Brown <neilb@xxxxxxx>
> Cc: Andrea Righi <andrea@xxxxxxxxxxxxxxx>
> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> Cc: Mike Hommey <mh@xxxxxxxxxxxx>
> Cc: Taras Glek <tglek@xxxxxxxxxxx>
> Cc: Dhaval Giani <dgiani@xxxxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxx>
> Cc: Michel Lespinasse <walken@xxxxxxxxxx>
> Cc: Minchan Kim <minchan@xxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx <linux-mm@xxxxxxxxx>
> 
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
> [jstultz: Extended to work with file pages]
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> ---
>  arch/x86/include/asm/pgtable_types.h |  2 ++
>  include/asm-generic/pgtable.h        | 11 +++++++++++
>  include/linux/vrange.h               |  2 ++
>  mm/memory.c                          | 23 +++++++++++++++++++++--
>  mm/vrange.c                          | 35 ++++++++++++++++++++++++++++++++++-
>  5 files changed, 70 insertions(+), 3 deletions(-)
> 

This patch fixes the problem Dhaval reported.