[ 054/143] ifb: fix rcu_sched self-detected stalls

Willy Tarreau
2014-05-12T01:51:53Z

From: dingtianhong <dingtianhong@huawei.com>

[ 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>
[wt: 2.6.32: cond_resched() needs linux/sched.h]
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
drivers/net/ifb.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index 030913f..cfd5510 100644
--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -33,6 +33,7 @@
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
+#include <linux/sched.h>
#include <net/pkt_sched.h>
#include <net/net_namespace.h>

@@ -269,8 +270,10 @@ 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();
--
1.7.12.2.21.g234cd45.dirty