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

[Bernard Metzler]

-----"Jason Gunthorpe" <jgg@xxxxxxxxxxxx> wrote: -----

>To: "Leon Romanovsky" <leon@xxxxxxxxxx>, "Bernard Metzler"
><bmt@xxxxxxxxxxxxxx>
>From: "Jason Gunthorpe" <jgg@xxxxxxxxxxxx>
>Date: 07/10/2019 07:52PM
>Cc: "Stephen Rothwell" <sfr@xxxxxxxxxxxxxxxx>, "Doug Ledford"
><dledford@xxxxxxxxxx>, "David Miller" <davem@xxxxxxxxxxxxx>,
>"Networking" <netdev@xxxxxxxxxxxxxxx>, "Linux Next Mailing List"
><linux-next@xxxxxxxxxxxxxxx>, "Linux Kernel Mailing List"
><linux-kernel@xxxxxxxxxxxxxxx>
>Subject: [EXTERNAL] Re: linux-next: build failure after merge of the
>net-next tree
>
>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@xxxxxxxxxxxx>
>> Date: Sun, 7 Jul 2019 10:43:42 +0300
>> Subject: [PATCH] Fixup to build SIW issue
>> 
>> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
>>  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
>

Hi Jason,

That listen will not sleep. The socket is just marked
listening. Accepting a new connection is handled asynchronously
by a work handler, kicked by a socket callback
(siw_cm_llp_state_change).

But, I think you are correct, we are missing the
rcu_read_lock/unlock around that iteration. Could we please add
that (see below)?

Thanks very much!
Bernard.

diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
index c883bf514341..c5c060103993 100644
--- a/drivers/infiniband/sw/siw/siw_cm.c
+++ b/drivers/infiniband/sw/siw/siw_cm.c
@@ -1976,6 +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));
 
+               rcu_read_lock();
                in_dev_for_each_ifa_rcu(ifa, in_dev) {
                        if (ipv4_is_zeronet(s_laddr.sin_addr.s_addr) ||
                            s_laddr.sin_addr.s_addr == ifa->ifa_address) {
@@ -1988,6 +1989,7 @@ int siw_create_listen(struct iw_cm_id *id, int backlog)
                                        listeners++;
                        }
                }
+               rcu_read_unlock();
                in_dev_put(in_dev);
        } else if (id->local_addr.ss_family == AF_INET6) {
                struct inet6_dev *in6_dev = in6_dev_get(dev);



>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);
>
>