ifb: fix rcu_sched self-detected stalls

[ Upstream commit 440d57bc5ff55ec1efb3efc9cbe9420b4bbdfefa ]

According to the commit 16b0dc29c1af9df341428f4c49ada4f626258082
(dummy: fix rcu_sched self-detected stalls)

Eric Dumazet fix the problem in dummy, but the ifb will occur the
same problem like the dummy modules.

Trying to "modprobe ifb numifbs=30000" triggers :

INFO: rcu_sched self-detected stall on CPU

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

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

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index 46b5f5f..4924a1e 100644 (file)
--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -291,8 +291,10 @@ static int __init ifb_init_module(void)
        rtnl_lock();
        err = __rtnl_link_register(&ifb_link_ops);
 
-       for (i = 0; i < numifbs && !err; i++)
+       for (i = 0; i < numifbs && !err; i++) {
                err = ifb_init_one(i);
+               cond_resched();
+       }
        if (err)
                __rtnl_link_unregister(&ifb_link_ops);
        rtnl_unlock();