malloc: Avoid premature fallback to mmap [BZ #20284]

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.

1 files changed, 6 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 437fb6d24e..e418cc0897 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+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.
+
 2016-06-21 Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
 	* misc/Makefile (tests): Add tst-preadvwritev and tst-preadvwritev64.