From: Eric Dumazet <edumazet@google.com>
Date: Sun, 10 Jun 2012 21:11:57 +0000 (+0000)
Subject: dummy: fix rcu_sched self-detected stalls
X-Git-Tag: firefly_0821_release~7541^2~1014
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=7dd0931198ce3e25901ffb56036bb070efe9f987;p=firefly-linux-kernel-4.4.55.git

dummy: fix rcu_sched self-detected stalls

[ Upstream commit 16b0dc29c1af9df341428f4c49ada4f626258082 ]

Trying to "modprobe dummy numdummies=30000" triggers :

INFO: rcu_sched self-detected stall on CPU { 8} (t=60000 jiffies)

After this splat, RTNL is locked and reboot is needed.

We must call cond_resched() to avoid this, even holding RTNL.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c
index 3fa19c162112..098ff315694f 100644
--- a/drivers/net/dummy.c
+++ b/drivers/net/dummy.c
@@ -37,6 +37,7 @@
 #include <linux/rtnetlink.h>
 #include <net/rtnetlink.h>
 #include <linux/u64_stats_sync.h>
+#include <linux/sched.h>
 
 static int numdummies = 1;
 
@@ -186,8 +187,10 @@ static int __init dummy_init_module(void)
 	rtnl_lock();
 	err = __rtnl_link_register(&dummy_link_ops);
 
-	for (i = 0; i < numdummies && !err; i++)
+	for (i = 0; i < numdummies && !err; i++) {
 		err = dummy_init_one();
+		cond_resched();
+	}
 	if (err < 0)
 		__rtnl_link_unregister(&dummy_link_ops);
 	rtnl_unlock();