From 18b48d5873a6fc8e0e6044ddb572fcda26988f19 Mon Sep 17 00:00:00 2001
From: Wen Congyang <wency@cn.fujitsu.com>
Date: Mon, 17 Sep 2012 14:08:55 -0700
Subject: [PATCH] memory hotplug: reset pgdat->kswapd to NULL if creating
kernel thread fails
If kthread_run() fails, pgdat->kswapd contains errno. When we stop this
thread, we only check whether pgdat->kswapd is NULL and access it. If
it contains errno, it will cause page fault. Reset pgdat->kswapd to
NULL when creating kernel thread fails can avoid this problem.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/vmscan.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8d01243d9560..99b434b674c0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3102,6 +3102,7 @@ int kswapd_run(int nid)
/* failure at boot is fatal */
BUG_ON(system_state == SYSTEM_BOOTING);
printk("Failed to start kswapd on node %d\n",nid);
+ pgdat->kswapd = NULL;
ret = -1;
}
return ret;
--
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