src/patches/glibc/glibc-rh1256812-4.patch

   1 commit 55765a349a96482207fbf927d3666a51878f973b
   2 Author: Josef Bacik <josef@toxicpanda.com>
   3 Date:   Wed Aug 19 14:06:56 2015 +0530
   4
   5     Don't fall back to mmap if the original arena is not corrupt
   6
   7     The new logic to find an uncontended non-corrupt arena misses a case
   8     where the current arena is contended, but is not corrupt.  In the
   9     degenerate case, this is the only arena.  In both cases, the logic
  10     falls back to using mmap despite there being an available arena.
  11
  12     Attached patch by Josef Bacik makes sure that all arenas are indeed
  13     corrupt before falling back to malloc.  Verified on x86_64.
  14
  15         * malloc/arena.c (reused_arena): return NULL only if all
  16         arenas are corrupt.
  17
  18 diff --git a/malloc/arena.c b/malloc/arena.c
  19 index 21ecc5a1..0424273 100644
  20 --- a/malloc/arena.c
  21 +++ b/malloc/arena.c
  22 @@ -823,16 +823,21 @@ reused_arena (mstate avoid_arena)
  23
  24    /* Make sure that the arena we get is not corrupted.  */
  25    mstate begin = result;
  26 +  bool looped = false;
  27 +
  28    while (arena_is_corrupt (result))
  29      {
  30        result = result->next;
  31        if (result == begin)
  32 -       break;
  33 +       {
  34 +         looped = true;
  35 +         break;
  36 +       }
  37      }
  38
  39    /* We could not find any arena that was either not corrupted or not the one
  40       we wanted to avoid.  */
  41 -  if (result == begin)
  42 +  if (looped)
  43      return NULL;
  44
  45    /* No arena available without contention.  Wait for the next in line.  */