From: Willy Tarreau <w@1wt.eu>
Date: Sun, 9 Aug 2009 07:09:54 +0000 (+0200)
Subject: [BUG] task: fix possible crash when some timeouts are not configured
X-Git-Tag: v1.4-dev2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=34e98ea70d09195e8e047b3ea22c23506598687d;p=thirdparty%2Fhaproxy.git

[BUG] task: fix possible crash when some timeouts are not configured

Cristian Ditoiu reported a major regression when testing 1.3.19 at
transfer.ro. It would crash within a few minutes while 1.3.15.10
was OK. He offered to help so we could run gdb and debug the crash
live. We finally found that the crash was the result of a regression
introduced by recent fix 814c978fb67782ceeaf1db74abfe7083938bedff
(task: fix possible timer drift after update) which makes it possible
for a tree walk to start from a detached task if this task has got
its timeout disabled due to a missing timeout.

The trivial fix below has been extensively tested and confirmed not
to crash anymore.

Special thanks to Cristian who spontaneously provided a lot of help
and trust to debug this issue which at first glance looked impossible
after reading the code and traces, but took less than an hour to spot
and fix when caught live in gdb ! That's really appreciated !
---

diff --git a/src/task.c b/src/task.c
index 3094fde7ef..268f8d9e97 100644
--- a/src/task.c
+++ b/src/task.c
@@ -155,9 +155,13 @@ void wake_expired_tasks(int *next)
 		 * to take care of this. Note that we might occasionally requeue it at
 		 * the same place, before <eb>, so we have to check if this happens,
 		 * and adjust <eb>, otherwise we may skip it which is not what we want.
+		 * We may also not requeue the task (and not point eb at it) if its
+		 * expiration time is not set.
 		 */
 		if (!tick_is_expired(task->expire, now_ms)) {
-			task_queue(task);
+			if (!tick_isset(task->expire))
+				continue;
+			__task_queue(task);
 			if (!eb || eb->key > task->wq.key)
 				eb = &task->wq;
 			continue;