* [2.23 COMMITTED] malloc: Avoid premature fallback to mmap [BZ #20284]
@ 2016-01-01 0:00 Florian Weimer
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From: Florian Weimer @ 2016-01-01 0:00 UTC (permalink / raw)
To: libc-stable
Before this change, the while loop in reused_arena which avoids
returning a corrupt arena would never execute its body if the selected
arena were not corrupt. As a result, result == begin after the loop,
and the function returns NULL, triggering fallback to mmap.
(cherry picked from commit a3b473373ee43a292f5ec68a7fda6b9cfb26a9b0)
2016-06-21 Florian Weimer <fweimer@redhat.com>
[BZ #20284]
* malloc/arena.c (reused_arena): Do not return NULL if we start
out with a non-corrupted arena.
diff --git a/malloc/arena.c b/malloc/arena.c
index 0e5cc0f..232b6a2 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -795,14 +795,12 @@ reused_arena (mstate avoid_arena)
{
result = result->next;
if (result == begin)
- break;
+ /* We looped around the arena list. We could not find any
+ arena that was either not corrupted or not the one we
+ wanted to avoid. */
+ return NULL;
}
- /* We could not find any arena that was either not corrupted or not the one
- we wanted to avoid. */
- if (result == begin || result == avoid_arena)
- return NULL;
-
/* No arena available without contention. Wait for the next in line. */
LIBC_PROBE (memory_arena_reuse_wait, 3, &result->mutex, result, avoid_arena);
(void) mutex_lock (&result->mutex);
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2016-01-01 0:00 [2.23 COMMITTED] malloc: Avoid premature fallback to mmap [BZ #20284] Florian Weimer
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