From: Larry Woodman <lwoodman@redhat.com>
Subject: [RHEL5 patch] Prevent OOM-kill of unkillable children or siblings
Date: Thu, 31 May 2007 14:17:50 -0400
Bugzilla: 222492
Message-Id: <465F114E.60706@redhat.com>
Changelog: [mm] Prevent OOM-kill of unkillable children or siblings


Abort the kill of a process if any of the threads have OOM_DISABLE set. 
Having this test here also prevents any OOM_DISABLE child of the "selected"
process from being killed.

The attached upstream patch fixes this problem and BZ 222492.



--- linux-2.6.18.noarch/mm/oom_kill.c.orig
+++ linux-2.6.18.noarch/mm/oom_kill.c
@@ -310,15 +310,23 @@ static int oom_kill_task(struct task_str
 	if (mm == NULL || mm == &init_mm)
 		return 1;
 
+	/*
+	 * Don't kill the process if any threads are set to OOM_DISABLE
+	 */
+	do_each_thread(g, q) {
+		if (q->mm == mm && p->oomkilladj == OOM_DISABLE)
+			return 1;
+	} while_each_thread(g, q);
+
 	__oom_kill_task(p, message);
 	/*
 	 * kill all processes that share the ->mm (i.e. all threads),
 	 * but are in a different thread group
 	 */
-	do_each_thread(g, q)
+	do_each_thread(g, q) {
 		if (q->mm == mm && q->tgid != p->tgid)
 			__oom_kill_task(q, message);
-	while_each_thread(g, q);
+	} while_each_thread(g, q);
 
 	return 0;
 }