linux-stable.git/net/tipc/socket.c, branch v4.19.151 Linux kernel stable tree tipc: fix shutdown() of connection oriented socket 2020-09-26T16:01:30+00:00 Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp 2020-09-05T06:14:47+00:00 0183a74c915882509f70c2ddc05bc9e6726cfb7c [ Upstream commit a4b5cc9e10803ecba64a7d54c0f47e4564b4a980 ] I confirmed that the problem fixed by commit 2a63866c8b51a3f7 ("tipc: fix shutdown() of connectionless socket") also applies to stream socket. ---------- #include <sys/socket.h> #include <unistd.h> #include <sys/wait.h> int main(int argc, char *argv[]) { int fds[2] = { -1, -1 }; socketpair(PF_TIPC, SOCK_STREAM /* or SOCK_DGRAM */, 0, fds); if (fork() == 0) _exit(read(fds[0], NULL, 1)); shutdown(fds[0], SHUT_RDWR); /* This must make read() return. */ wait(NULL); /* To be woken up by _exit(). */ return 0; } ---------- Since shutdown(SHUT_RDWR) should affect all processes sharing that socket, unconditionally setting sk->sk_shutdown to SHUTDOWN_MASK will be the right behavior. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit a4b5cc9e10803ecba64a7d54c0f47e4564b4a980 ]

I confirmed that the problem fixed by commit 2a63866c8b51a3f7 ("tipc: fix
shutdown() of connectionless socket") also applies to stream socket.

----------
#include <sys/socket.h>
#include <unistd.h>
#include <sys/wait.h>

int main(int argc, char *argv[])
{
        int fds[2] = { -1, -1 };
        socketpair(PF_TIPC, SOCK_STREAM /* or SOCK_DGRAM */, 0, fds);
        if (fork() == 0)
                _exit(read(fds[0], NULL, 1));
        shutdown(fds[0], SHUT_RDWR); /* This must make read() return. */
        wait(NULL); /* To be woken up by _exit(). */
        return 0;
}
----------

Since shutdown(SHUT_RDWR) should affect all processes sharing that socket,
unconditionally setting sk->sk_shutdown to SHUTDOWN_MASK will be the right
behavior.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: fix shutdown() of connectionless socket 2020-09-12T11:40:22+00:00 Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp 2020-09-02T13:44:16+00:00 553d1bb7f4d1d2b86b7527c10be31b2f5f78bd8c [ Upstream commit 2a63866c8b51a3f72cea388dfac259d0e14c4ba6 ] syzbot is reporting hung task at nbd_ioctl() [1], for there are two problems regarding TIPC's connectionless socket's shutdown() operation. ---------- #include <fcntl.h> #include <sys/socket.h> #include <sys/ioctl.h> #include <linux/nbd.h> #include <unistd.h> int main(int argc, char *argv[]) { const int fd = open("/dev/nbd0", 3); alarm(5); ioctl(fd, NBD_SET_SOCK, socket(PF_TIPC, SOCK_DGRAM, 0)); ioctl(fd, NBD_DO_IT, 0); /* To be interrupted by SIGALRM. */ return 0; } ---------- One problem is that wait_for_completion() from flush_workqueue() from nbd_start_device_ioctl() from nbd_ioctl() cannot be completed when nbd_start_device_ioctl() received a signal at wait_event_interruptible(), for tipc_shutdown() from kernel_sock_shutdown(SHUT_RDWR) from nbd_mark_nsock_dead() from sock_shutdown() from nbd_start_device_ioctl() is failing to wake up a WQ thread sleeping at wait_woken() from tipc_wait_for_rcvmsg() from sock_recvmsg() from sock_xmit() from nbd_read_stat() from recv_work() scheduled by nbd_start_device() from nbd_start_device_ioctl(). Fix this problem by always invoking sk->sk_state_change() (like inet_shutdown() does) when tipc_shutdown() is called. The other problem is that tipc_wait_for_rcvmsg() cannot return when tipc_shutdown() is called, for tipc_shutdown() sets sk->sk_shutdown to SEND_SHUTDOWN (despite "how" is SHUT_RDWR) while tipc_wait_for_rcvmsg() needs sk->sk_shutdown set to RCV_SHUTDOWN or SHUTDOWN_MASK. Fix this problem by setting sk->sk_shutdown to SHUTDOWN_MASK (like inet_shutdown() does) when the socket is connectionless. [1] https://syzkaller.appspot.com/bug?id=3fe51d307c1f0a845485cf1798aa059d12bf18b2 Reported-by: syzbot <syzbot+e36f41d207137b5d12f7@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 2a63866c8b51a3f72cea388dfac259d0e14c4ba6 ]

syzbot is reporting hung task at nbd_ioctl() [1], for there are two
problems regarding TIPC's connectionless socket's shutdown() operation.

----------
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/nbd.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
        const int fd = open("/dev/nbd0", 3);
        alarm(5);
        ioctl(fd, NBD_SET_SOCK, socket(PF_TIPC, SOCK_DGRAM, 0));
        ioctl(fd, NBD_DO_IT, 0); /* To be interrupted by SIGALRM. */
        return 0;
}
----------

One problem is that wait_for_completion() from flush_workqueue() from
nbd_start_device_ioctl() from nbd_ioctl() cannot be completed when
nbd_start_device_ioctl() received a signal at wait_event_interruptible(),
for tipc_shutdown() from kernel_sock_shutdown(SHUT_RDWR) from
nbd_mark_nsock_dead() from sock_shutdown() from nbd_start_device_ioctl()
is failing to wake up a WQ thread sleeping at wait_woken() from
tipc_wait_for_rcvmsg() from sock_recvmsg() from sock_xmit() from
nbd_read_stat() from recv_work() scheduled by nbd_start_device() from
nbd_start_device_ioctl(). Fix this problem by always invoking
sk->sk_state_change() (like inet_shutdown() does) when tipc_shutdown() is
called.

The other problem is that tipc_wait_for_rcvmsg() cannot return when
tipc_shutdown() is called, for tipc_shutdown() sets sk->sk_shutdown to
SEND_SHUTDOWN (despite "how" is SHUT_RDWR) while tipc_wait_for_rcvmsg()
needs sk->sk_shutdown set to RCV_SHUTDOWN or SHUTDOWN_MASK. Fix this
problem by setting sk->sk_shutdown to SHUTDOWN_MASK (like inet_shutdown()
does) when the socket is connectionless.

[1] https://syzkaller.appspot.com/bug?id=3fe51d307c1f0a845485cf1798aa059d12bf18b2

Reported-by: syzbot <syzbot+e36f41d207137b5d12f7@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: clean up skb list lock handling on send path 2020-07-29T08:16:47+00:00 Jon Maloy jon.maloy@ericsson.com 2019-08-15T14:42:50+00:00 675f4bbcd68330d2d0c96e1f716886727ad7dd1a commit e654f9f53b45fde3fcc8051830b212c7a8f36148 upstream. The policy for handling the skb list locks on the send and receive paths is simple. - On the send path we never need to grab the lock on the 'xmitq' list when the destination is an exernal node. - On the receive path we always need to grab the lock on the 'inputq' list, irrespective of source node. However, when transmitting node local messages those will eventually end up on the receive path of a local socket, meaning that the argument 'xmitq' in tipc_node_xmit() will become the 'ínputq' argument in the function tipc_sk_rcv(). This has been handled by always initializing the spinlock of the 'xmitq' list at message creation, just in case it may end up on the receive path later, and despite knowing that the lock in most cases never will be used. This approach is inaccurate and confusing, and has also concealed the fact that the stated 'no lock grabbing' policy for the send path is violated in some cases. We now clean up this by never initializing the lock at message creation, instead doing this at the moment we find that the message actually will enter the receive path. At the same time we fix the four locations where we incorrectly access the spinlock on the send/error path. This patch also reverts commit d12cffe9329f ("tipc: ensure head->lock is initialised") which has now become redundant. CC: Eric Dumazet <edumazet@google.com> Reported-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> [acj: backport v4.19 -stable - adjust context - skipped the hunk modifying non-existent function tipc_mcast_send_sync - additional comment ] Signed-off-by: Aviraj CJ <acj@cisco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e654f9f53b45fde3fcc8051830b212c7a8f36148 upstream.

The policy for handling the skb list locks on the send and receive paths
is simple.

- On the send path we never need to grab the lock on the 'xmitq' list
  when the destination is an exernal node.

- On the receive path we always need to grab the lock on the 'inputq'
  list, irrespective of source node.

However, when transmitting node local messages those will eventually
end up on the receive path of a local socket, meaning that the argument
'xmitq' in tipc_node_xmit() will become the 'ínputq' argument in  the
function tipc_sk_rcv(). This has been handled by always initializing
the spinlock of the 'xmitq' list at message creation, just in case it
may end up on the receive path later, and despite knowing that the lock
in most cases never will be used.

This approach is inaccurate and confusing, and has also concealed the
fact that the stated 'no lock grabbing' policy for the send path is
violated in some cases.

We now clean up this by never initializing the lock at message creation,
instead doing this at the moment we find that the message actually will
enter the receive path. At the same time we fix the four locations
where we incorrectly access the spinlock on the send/error path.

This patch also reverts commit d12cffe9329f ("tipc: ensure head->lock
is initialised") which has now become redundant.

CC: Eric Dumazet <edumazet@google.com>
Reported-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[acj: backport v4.19 -stable
- adjust context
- skipped the hunk modifying non-existent function tipc_mcast_send_sync
- additional comment ]
Signed-off-by: Aviraj CJ <acj@cisco.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: fix wrong timeout input for tipc_wait_for_cond() 2020-01-27T13:49:52+00:00 Tung Nguyen tung.q.nguyen@dektech.com.au 2019-11-28T03:10:07+00:00 b8f60290aecef29c9e96cdfeaa5de7835ec12af6 commit 12db3c8083fcab4270866a88191933f2d9f24f89 upstream. In function __tipc_shutdown(), the timeout value passed to tipc_wait_for_cond() is not jiffies. This commit fixes it by converting that value from milliseconds to jiffies. Fixes: 365ad353c256 ("tipc: reduce risk of user starvation during link congestion") Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 12db3c8083fcab4270866a88191933f2d9f24f89 upstream.

In function __tipc_shutdown(), the timeout value passed to
tipc_wait_for_cond() is not jiffies.

This commit fixes it by converting that value from milliseconds
to jiffies.

Fixes: 365ad353c256 ("tipc: reduce risk of user starvation during link congestion")
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: use skb_queue_empty_lockless() in poll() handlers 2019-11-10T10:27:48+00:00 Eric Dumazet edumazet@google.com 2019-10-24T05:44:50+00:00 eaf548feaa17308317bdac2903c1be820e5c186a [ Upstream commit 3ef7cf57c72f32f61e97f8fa401bc39ea1f1a5d4 ] Many poll() handlers are lockless. Using skb_queue_empty_lockless() instead of skb_queue_empty() is more appropriate. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 3ef7cf57c72f32f61e97f8fa401bc39ea1f1a5d4 ]

Many poll() handlers are lockless. Using skb_queue_empty_lockless()
instead of skb_queue_empty() is more appropriate.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: fix hanging clients using poll with EPOLLOUT flag 2019-05-16T17:41:31+00:00 Parthasarathy Bhuvaragan parthasarathy.bhuvaragan@gmail.com 2019-05-09T05:13:42+00:00 afa485dc6f17dcfff2e8179cb67f1939660b3bed [ Upstream commit ff946833b70e0c7f93de9a3f5b329b5ae2287b38 ] commit 517d7c79bdb398 ("tipc: fix hanging poll() for stream sockets") introduced a regression for clients using non-blocking sockets. After the commit, we send EPOLLOUT event to the client even in TIPC_CONNECTING state. This causes the subsequent send() to fail with ENOTCONN, as the socket is still not in TIPC_ESTABLISHED state. In this commit, we: - improve the fix for hanging poll() by replacing sk_data_ready() with sk_state_change() to wake up all clients. - revert the faulty updates introduced by commit 517d7c79bdb398 ("tipc: fix hanging poll() for stream sockets"). Fixes: 517d7c79bdb398 ("tipc: fix hanging poll() for stream sockets") Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@gmail.com> Acked-by: Jon Maloy <jon.maloy@ericsson.se> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit ff946833b70e0c7f93de9a3f5b329b5ae2287b38 ]

commit 517d7c79bdb398 ("tipc: fix hanging poll() for stream sockets")
introduced a regression for clients using non-blocking sockets.
After the commit, we send EPOLLOUT event to the client even in
TIPC_CONNECTING state. This causes the subsequent send() to fail
with ENOTCONN, as the socket is still not in TIPC_ESTABLISHED state.

In this commit, we:
- improve the fix for hanging poll() by replacing sk_data_ready()
  with sk_state_change() to wake up all clients.
- revert the faulty updates introduced by commit 517d7c79bdb398
  ("tipc: fix hanging poll() for stream sockets").

Fixes: 517d7c79bdb398 ("tipc: fix hanging poll() for stream sockets")
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@gmail.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: allow service ranges to be connect()'ed on RDM/DGRAM 2019-04-03T04:26:18+00:00 Erik Hugne erik.hugne@gmail.com 2019-03-17T17:46:42+00:00 24d1a6259706f03aa2057359685ef8ea77f69e38 [ Upstream commit ea239314fe42ace880bdd834256834679346c80e ] We move the check that prevents connecting service ranges to after the RDM/DGRAM check, and move address sanity control to a separate function that also validates the service range. Fixes: 23998835be98 ("tipc: improve address sanity check in tipc_connect()") Signed-off-by: Erik Hugne <erik.hugne@gmail.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit ea239314fe42ace880bdd834256834679346c80e ]

We move the check that prevents connecting service ranges to after
the RDM/DGRAM check, and move address sanity control to a separate
function that also validates the service range.

Fixes: 23998835be98 ("tipc: improve address sanity check in tipc_connect()")
Signed-off-by: Erik Hugne <erik.hugne@gmail.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: fix race condition causing hung sendto 2019-03-10T06:17:18+00:00 Tung Nguyen tung.q.nguyen@dektech.com.au 2019-02-25T03:57:20+00:00 ab04570d82b164daca4917c459c152dfb3839448 [ Upstream commit bfd07f3dd4f111b884d7922b37eb239280f83d8c ] When sending multicast messages via blocking socket, if sending link is congested (tsk->cong_link_cnt is set to 1), the sending thread will be put into sleeping state. However, tipc_sk_filter_rcv() is called under socket spin lock but tipc_wait_for_cond() is not. So, there is no guarantee that the setting of tsk->cong_link_cnt to 0 in tipc_sk_proto_rcv() in CPU-1 will be perceived by CPU-0. If that is the case, the sending thread in CPU-0 after being waken up, will continue to see tsk->cong_link_cnt as 1 and put the sending thread into sleeping state again. The sending thread will sleep forever. CPU-0 | CPU-1 tipc_wait_for_cond() | { | // condition_ = !tsk->cong_link_cnt | while ((rc_ = !(condition_))) { | ... | release_sock(sk_); | wait_woken(); | | if (!sock_owned_by_user(sk)) | tipc_sk_filter_rcv() | { | ... | tipc_sk_proto_rcv() | { | ... | tsk->cong_link_cnt--; | ... | sk->sk_write_space(sk); | ... | } | ... | } sched_annotate_sleep(); | lock_sock(sk_); | remove_wait_queue(); | } | } | This commit fixes it by adding memory barrier to tipc_sk_proto_rcv() and tipc_wait_for_cond(). Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit bfd07f3dd4f111b884d7922b37eb239280f83d8c ]

When sending multicast messages via blocking socket,
if sending link is congested (tsk->cong_link_cnt is set to 1),
the sending thread will be put into sleeping state. However,
tipc_sk_filter_rcv() is called under socket spin lock but
tipc_wait_for_cond() is not. So, there is no guarantee that
the setting of tsk->cong_link_cnt to 0 in tipc_sk_proto_rcv() in
CPU-1 will be perceived by CPU-0. If that is the case, the sending
thread in CPU-0 after being waken up, will continue to see
tsk->cong_link_cnt as 1 and put the sending thread into sleeping
state again. The sending thread will sleep forever.

CPU-0                                | CPU-1
tipc_wait_for_cond()                 |
{                                    |
 // condition_ = !tsk->cong_link_cnt |
 while ((rc_ = !(condition_))) {     |
  ...                                |
  release_sock(sk_);                 |
  wait_woken();                      |
                                     | if (!sock_owned_by_user(sk))
                                     |  tipc_sk_filter_rcv()
                                     |  {
                                     |   ...
                                     |   tipc_sk_proto_rcv()
                                     |   {
                                     |    ...
                                     |    tsk->cong_link_cnt--;
                                     |    ...
                                     |    sk->sk_write_space(sk);
                                     |    ...
                                     |   }
                                     |   ...
                                     |  }
  sched_annotate_sleep();            |
  lock_sock(sk_);                    |
  remove_wait_queue();               |
 }                                   |
}                                    |

This commit fixes it by adding memory barrier to tipc_sk_proto_rcv()
and tipc_wait_for_cond().

Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: fix RDM/DGRAM connect() regression 2019-03-10T06:17:17+00:00 Erik Hugne erik.hugne@gmail.com 2019-03-04T22:26:10+00:00 8d1b9800c1ea9f3c27a2a724e0024a30784b39a9 [ Upstream commit 0e63208915a8d7590d0a6218dadb2a6a00ac705a ] Fix regression bug introduced in commit 365ad353c256 ("tipc: reduce risk of user starvation during link congestion") Only signal -EDESTADDRREQ for RDM/DGRAM if we don't have a cached sockaddr. Fixes: 365ad353c256 ("tipc: reduce risk of user starvation during link congestion") Signed-off-by: Erik Hugne <erik.hugne@gmail.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 0e63208915a8d7590d0a6218dadb2a6a00ac705a ]

Fix regression bug introduced in
commit 365ad353c256 ("tipc: reduce risk of user starvation during link
congestion")

Only signal -EDESTADDRREQ for RDM/DGRAM if we don't have a cached
sockaddr.

Fixes: 365ad353c256 ("tipc: reduce risk of user starvation during link congestion")
Signed-off-by: Erik Hugne <erik.hugne@gmail.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tipc: check group dests after tipc_wait_for_cond() 2019-01-09T16:38:34+00:00 Cong Wang xiyou.wangcong@gmail.com 2018-12-17T07:25:12+00:00 7942d5be49224bbd7cc8b5c589e1e670651021d1 [ Upstream commit 3c6306d44082ef007a258ae1b86ea58e6974ee3f ] Similar to commit 143ece654f9f ("tipc: check tsk->group in tipc_wait_for_cond()") we have to reload grp->dests too after we re-take the sock lock. This means we need to move the dsts check after tipc_wait_for_cond() too. Fixes: 75da2163dbb6 ("tipc: introduce communication groups") Reported-and-tested-by: syzbot+99f20222fc5018d2b97a@syzkaller.appspotmail.com Cc: Ying Xue <ying.xue@windriver.com> Cc: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 3c6306d44082ef007a258ae1b86ea58e6974ee3f ]

Similar to commit 143ece654f9f ("tipc: check tsk->group in tipc_wait_for_cond()")
we have to reload grp->dests too after we re-take the sock lock.
This means we need to move the dsts check after tipc_wait_for_cond()
too.

Fixes: 75da2163dbb6 ("tipc: introduce communication groups")
Reported-and-tested-by: syzbot+99f20222fc5018d2b97a@syzkaller.appspotmail.com
Cc: Ying Xue <ying.xue@windriver.com>
Cc: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>