1. 16 Dec, 2014 2 commits
    • Hugh Dickins's avatar
      mm: fix swapoff hang after page migration and fork · 45422468
      Hugh Dickins authored
      commit 2022b4d1 upstream.
      
      I've been seeing swapoff hangs in recent testing: it's cycling around
      trying unsuccessfully to find an mm for some remaining pages of swap.
      
      I have been exercising swap and page migration more heavily recently,
      and now notice a long-standing error in copy_one_pte(): it's trying to
      add dst_mm to swapoff's mmlist when it finds a swap entry, but is doing
      so even when it's a migration entry or an hwpoison entry.
      
      Which wouldn't matter much, except it adds dst_mm next to src_mm,
      assuming src_mm is already on the mmlist: which may not be so.  Then if
      pages are later swapped out from dst_mm, swapoff won't be able to find
      where to replace them.
      
      There's already a !non_swap_entry() test for stats: move that up before
      the swap_duplicate() and the addition to mmlist.
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Cc: Kelley Nielsen <kelleynnn@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      45422468
    • Weijie Yang's avatar
      mm: frontswap: invalidate expired data on a dup-store failure · 22fff283
      Weijie Yang authored
      commit fb993fa1 upstream.
      
      If a frontswap dup-store failed, it should invalidate the expired page
      in the backend, or it could trigger some data corruption issue.
      Such as:
       1. use zswap as the frontswap backend with writeback feature
       2. store a swap page(version_1) to entry A, success
       3. dup-store a newer page(version_2) to the same entry A, fail
       4. use __swap_writepage() write version_2 page to swapfile, success
       5. zswap do shrink, writeback version_1 page to swapfile
       6. version_2 page is overwrited by version_1, data corrupt.
      
      This patch fixes this issue by invalidating expired data immediately
      when meet a dup-store failure.
      Signed-off-by: default avatarWeijie Yang <weijie.yang@samsung.com>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Seth Jennings <sjennings@variantweb.net>
      Cc: Dan Streetman <ddstreet@ieee.org>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Bob Liu <bob.liu@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      22fff283
  2. 06 Dec, 2014 38 commits