From 5c49abfcf3fd36957eef8e38a179fdba5e8a6c8d Mon Sep 17 00:00:00 2001
From: Tilghman Lesher <tilghman@meg.abyt.es>
Date: Mon, 14 Feb 2011 20:18:02 +0000
Subject: [PATCH] Merged revisions 307793 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.8
................
r307793 | tilghman | 2011-02-14 14:16:55 -0600 (Mon, 14 Feb 2011) | 15 lines
Merged revisions 307792 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.6.2
........
r307792 | tilghman | 2011-02-14 14:10:28 -0600 (Mon, 14 Feb 2011) | 8 lines
Increment usage count at first reference, to avoid a race condition with many threads creating connections all at once.
(issue #18156)
Reported by: asgaroth
Patches:
20110214__issue18156.diff.txt uploaded by tilghman (license 14)
Tested by: tilghman
........
................
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@307795 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
res/res_odbc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/res/res_odbc.c b/res/res_odbc.c
index 84d7284bbc..1af8bbafd6 100644
--- a/res/res_odbc.c
+++ b/res/res_odbc.c
@@ -1218,13 +1218,14 @@ struct odbc_obj *_ast_odbc_request_obj2(const char *name, struct ast_flags flags
if (obj) {
ast_assert(ao2_ref(obj, 0) > 1);
}
- if (!obj && (class->count < class->limit) &&
+ if (!obj && (ast_atomic_fetchadd_int(&class->count, +1) < class->limit) &&
(time(NULL) > class->last_negative_connect.tv_sec + class->negative_connection_cache.tv_sec)) {
obj = ao2_alloc(sizeof(*obj), odbc_obj_destructor);
if (!obj) {
class->count--;
ao2_ref(class, -1);
ast_debug(3, "Unable to allocate object\n");
+ ast_atomic_fetchadd_int(&class->count, -1);
return NULL;
}
ast_assert(ao2_ref(obj, 0) == 1);
@@ -1235,14 +1236,18 @@ struct odbc_obj *_ast_odbc_request_obj2(const char *name, struct ast_flags flags
if (odbc_obj_connect(obj) == ODBC_FAIL) {
ast_log(LOG_WARNING, "Failed to connect to %s\n", name);
ao2_ref(obj, -1);
- ast_assert(ao2_ref(class, 0) > 0);
obj = NULL;
+ ast_assert(ao2_ref(class, 0) > 0);
+ ast_atomic_fetchadd_int(&class->count, -1);
} else {
obj->used = 1;
ao2_link(obj->parent->obj_container, obj);
- ast_atomic_fetchadd_int(&obj->parent->count, +1);
}
} else {
+ /* If construction fails due to the limit (or negative timecache), reverse our increment. */
+ if (!obj) {
+ ast_atomic_fetchadd_int(&class->count, -1);
+ }
/* Object is not constructed, so delete outstanding reference to class. */
ao2_ref(class, -1);
class = NULL;
--
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