[ 034/187] dummy: fix rcu_sched self-detected stalls

Greg Kroah-Hartman
2012-07-12T22:37:38Z

From: Eric Dumazet <edumazet@google.com>

[ 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>
---
drivers/net/dummy.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/dummy.c
+++ b/drivers/net/dummy.c
@@ -187,8 +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();