Patchwork [62/75] ifb: fix rcu_sched self-detected stalls

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Submitter Kamal Mostafa
Date July 30, 2013, 6:45 p.m.
Message ID <1375209919-1768-29-git-send-email-kamal@canonical.com>
Download mbox | patch
Permalink /patch/263503/
State New
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Kamal Mostafa - July 30, 2013, 6:45 p.m.
3.8.13.6 -stable review patch.  If anyone has any objections, please let me know.

------------------

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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 drivers/net/ifb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Patch

diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index 344dceb..04ab337 100644
--- 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();