Subject: Re: Re: Re: linux-next: build failure after merge of the net-next tree

From: Jason Gunthorpe <[email-masked]>
Date: Thu, 11 Jul 2019 14:33:07 +0000

On Thu, Jul 11, 2019 at 12:29:21PM +0000, Bernard Metzler wrote:
> 
> >To: "Bernard Metzler" <[email-masked]>
> >From: "Jason Gunthorpe" <[email-masked]>
> >Date: 07/11/2019 01:53PM
> >Cc: "Leon Romanovsky" <[email-masked]>, "Stephen Rothwell"
> ><[email-masked]>, "Doug Ledford" <[email-masked]>, "David
> >Miller" <[email-masked]>, "Networking" <[email-masked]>,
> >"Linux Next Mailing List" <[email-masked]>, "Linux Kernel
> >Mailing List" <[email-masked]>
> >Subject: [EXTERNAL] Re: Re: linux-next: build failure after merge of
> >the net-next tree
> >
> >On Thu, Jul 11, 2019 at 08:00:49AM +0000, Bernard Metzler wrote:
> >
> >> That listen will not sleep. The socket is just marked
> >> listening. 
> >
> >Eh? siw_listen_address() calls siw_cep_alloc() which does:
> >
> >	struct siw_cep *cep = kzalloc(sizeof(*cep), GFP_KERNEL);
> >
> >Which is sleeping. Many other cases too.
> >
> >Jason
> >
> >
> Ah, true! I was after really deep sleeps like user level
> socket accept() calls ;) So you are correct of course.

I've added this patch to the rdma tree to fix the missing locking.

The merge resolution will be simply swapping
for_ifa to in_dev_for_each_ifa_rtnl.

Jason

>From c421651fa2295d1219c36674c7eb8c574542ceea Mon Sep 17 00:00:00 2001
From: Jason Gunthorpe <[email-masked]>
Date: Thu, 11 Jul 2019 11:29:42 -0300
Subject: [PATCH] RDMA/siw: Add missing rtnl_lock around access to ifa

ifa is protected by rcu or rtnl, add the missing locking. In this case we
have to use rtnl since siw_listen_address() is sleeping.

Fixes: 6c52fdc244b5 ("rdma/siw: connection management")
Reviewed-by: Bernard Metzler <[email-masked]>
Signed-off-by: Jason Gunthorpe <[email-masked]>
---
 drivers/infiniband/sw/siw/siw_cm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
index 8e618cb7261f62..c25be723c15b64 100644
--- a/drivers/infiniband/sw/siw/siw_cm.c
+++ b/drivers/infiniband/sw/siw/siw_cm.c
@@ -1975,6 +1975,7 @@ int siw_create_listen(struct iw_cm_id *id, int backlog)
 			id, &s_laddr.sin_addr, ntohs(s_laddr.sin_port),
 			&s_raddr->sin_addr, ntohs(s_raddr->sin_port));
 
+		rtnl_lock();
 		for_ifa(in_dev)
 		{
 			if (ipv4_is_zeronet(s_laddr.sin_addr.s_addr) ||
@@ -1989,6 +1990,7 @@ int siw_create_listen(struct iw_cm_id *id, int backlog)
 			}
 		}
 		endfor_ifa(in_dev);
+		rtnl_unlock();
 		in_dev_put(in_dev);
 	} else if (id->local_addr.ss_family == AF_INET6) {
 		struct inet6_dev *in6_dev = in6_dev_get(dev);
-- 
2.21.0