Re: linux-2.4.27 released

[William Lee Irwin III <wli@holomorphy.com>]

On Thu, Aug 12, 2004 at 11:17:12AM -0700, William Lee Irwin III wrote:
> This patch by nature corrects two apparent bugs which are really one
> bug. p->mm can become NULL while traversing the tasklist. The two
> effects are first that kernel threads appear to be killed. The second
> is that the OOM killing process fails to actually shoot down all threads
> of the chosen process, and so fails to reclaim the memory it intended to.
> oom_kill_task() consists primarily of the expansion of the 2.6 inline
> function get_task_mm().

Incremental atop the mm reference patch:

out_of_memory() attempts to determine whether one jiffies-valued
variable refers to a point in time preceding another jiffies-valued
variable, but does not do so in a jiffies wrap -safe fashion. The
following patch corrects this by using the expansion of the 2.6
macro time_after() to check this condition.

Index: linux-2.4/mm/oom_kill.c
===================================================================
--- linux-2.4.orig/mm/oom_kill.c	2004-06-23 19:41:08.000000000 -0700
+++ linux-2.4/mm/oom_kill.c	2004-06-23 19:50:59.000000000 -0700
@@ -289,7 +289,7 @@
 	spin_lock(&oom_lock);
 
 reset:
-	if (first < now)
+	if ((long)first - (long)now < 0)
 		first = now;
 	count = 0;