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

Stephen Rothwell
2019-07-11T01:51:01Z

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Hi all,

On Wed, 10 Jul 2019 17:52:17 +0000 Jason Gunthorpe <jgg@mellanox.com> wrote:
>
> On Tue, Jul 09, 2019 at 09:43:46AM +0300, Leon Romanovsky wrote:
> > On Tue, Jul 09, 2019 at 01:56:36PM +1000, Stephen Rothwell wrote:
> > > Hi all,
> > >
> > > After merging the net-next tree, today's linux-next build (x86_64
> > > allmodconfig) failed like this:
> > >
> > > drivers/infiniband/sw/siw/siw_cm.c: In function 'siw_create_listen':
> > > drivers/infiniband/sw/siw/siw_cm.c:1978:3: error: implicit declaration of function 'for_ifa'; did you mean 'fork_idle'? [-Werror=implicit-function-declaration]
> > > for_ifa(in_dev)
> > > ^~~~~~~
> > > fork_idle
> > > drivers/infiniband/sw/siw/siw_cm.c:1978:18: error: expected ';' before '{' token
> > > for_ifa(in_dev)
> > > ^
> > > ;
> > > {
> > > ~
> > >
> > > Caused by commit
> > >
> > > 6c52fdc244b5 ("rdma/siw: connection management")
> > >
> > > from the rdma tree. I don't know why this didn't fail after I mereged
> > > that tree.
> >
> > I had the same question, because I have this fix for a couple of days already.
> >
> > From 56c9e15ec670af580daa8c3ffde9503af3042d67 Mon Sep 17 00:00:00 2001
> > From: Leon Romanovsky <leonro@mellanox.com>
> > Date: Sun, 7 Jul 2019 10:43:42 +0300
> > Subject: [PATCH] Fixup to build SIW issue
> >
> > Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> > drivers/infiniband/sw/siw/siw_cm.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
> > index 8e618cb7261f..c883bf514341 100644
> > +++ b/drivers/infiniband/sw/siw/siw_cm.c
> > @@ -1954,6 +1954,7 @@ static void siw_drop_listeners(struct iw_cm_id *id)
> > int siw_create_listen(struct iw_cm_id *id, int backlog)
> > {
> > struct net_device *dev = to_siw_dev(id->device)->netdev;
> > + const struct in_ifaddr *ifa;
> > int rv = 0, listeners = 0;
> >
> > siw_dbg(id->device, "id 0x%p: backlog %d\n", id, backlog);
> > @@ -1975,8 +1976,7 @@ 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));
> >
> > - for_ifa(in_dev)
> > - {
> > + in_dev_for_each_ifa_rcu(ifa, in_dev) {
> > if (ipv4_is_zeronet(s_laddr.sin_addr.s_addr) ||
>
> Hum. There is no rcu lock held here and we can't use RCU anyhow as
> siw_listen_address will sleep.
>
> I think this needs to use rtnl, as below. Bernard, please urgently
> confirm. Thanks
>
> diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
> index 8e618cb7261f62..ee98e96a5bfaba 100644
> --- a/drivers/infiniband/sw/siw/siw_cm.c
> +++ b/drivers/infiniband/sw/siw/siw_cm.c
> @@ -1965,6 +1965,7 @@ int siw_create_listen(struct iw_cm_id *id, int backlog)
> */
> if (id->local_addr.ss_family == AF_INET) {
> struct in_device *in_dev = in_dev_get(dev);
> + const struct in_ifaddr *ifa;
> struct sockaddr_in s_laddr, *s_raddr;
>
> memcpy(&s_laddr, &id->local_addr, sizeof(s_laddr));
> @@ -1975,8 +1976,8 @@ 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));
>
> - for_ifa(in_dev)
> - {
> + rtnl_lock();
> + in_dev_for_each_ifa_rtnl(ifa, in_dev) {
> if (ipv4_is_zeronet(s_laddr.sin_addr.s_addr) ||
> s_laddr.sin_addr.s_addr == ifa->ifa_address) {
> s_laddr.sin_addr.s_addr = ifa->ifa_address;
> @@ -1988,7 +1989,7 @@ int siw_create_listen(struct iw_cm_id *id, int backlog)
> listeners++;
> }
> }
> - 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);

So today this failed to build after I merged the rdma tree (previously
it didn;t until after the net-next tree was merged (I assume a
dependency changed). It failed because in_dev_for_each_ifa_rcu (and
in_dev_for_each_ifa_rtnl) is only defined in a commit in the net-next
tree :-(

I have disabled the driver again.

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Cheers,
Stephen Rothwell

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