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authorFlorian Weimer <fweimer@redhat.com>2016-06-21 21:29:21 +0200
committerFlorian Weimer <fweimer@redhat.com>2016-06-21 21:29:21 +0200
commita3b473373ee43a292f5ec68a7fda6b9cfb26a9b0 (patch)
treeceb68dd3002c2f0a39b19260f3cc1011bfa6606e
parent4751bbe2ad4d1bfa05774e29376d553ecfe563b0 (diff)
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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.
-rw-r--r--ChangeLog6
-rw-r--r--malloc/arena.c10
2 files changed, 10 insertions, 6 deletions
diff --git a/ChangeLog b/ChangeLog
index 437fb6d..e418cc0 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.
diff --git a/malloc/arena.c b/malloc/arena.c
index ed5a4d5..229783f 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -771,14 +771,12 @@ 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);