kernel/linux.git/net/tipc/socket.c, branch linux-4.20.y

tipc: fix race condition causing hung sendto

2019-03-10T06:10:13+00:00

[ 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 Signed-off-by: Tung Nguyen Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tipc: fix RDM/DGRAM connect() regression

2019-03-10T06:10:11+00:00

[ 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 Signed-off-by: Jon Maloy Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tipc: check group dests after tipc_wait_for_cond()

2018-12-18T23:44:23+00:00

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 Cc: Jon Maloy Signed-off-by: Cong Wang Acked-by: Jon Maloy Signed-off-by: David S. Miller

tipc: check tsk->group in tipc_wait_for_cond()

2018-12-14T23:48:49+00:00

tipc_wait_for_cond() drops socket lock before going to sleep, but tsk->group could be freed right after that release_sock(). So we have to re-check and reload tsk->group after it wakes up. After this patch, tipc_wait_for_cond() returns -ERESTARTSYS when tsk->group is NULL, instead of continuing with the assumption of a non-NULL tsk->group. (It looks like 'dsts' should be re-checked and reloaded too, but it is a different bug.) Similar for tipc_send_group_unicast() and tipc_send_group_anycast(). Reported-by: syzbot+10a9db47c3a0e13eb31c@syzkaller.appspotmail.com Fixes: b7d42635517f ("tipc: introduce flow control for group broadcast messages") Fixes: ee106d7f942d ("tipc: introduce group anycast messaging") Fixes: 27bd9ec027f3 ("tipc: introduce group unicast messaging") Cc: Ying Xue Cc: Jon Maloy Signed-off-by: Cong Wang Acked-by: Ying Xue Signed-off-by: David S. Miller

tipc: use lock_sock() in tipc_sk_reinit()

2018-12-14T21:16:33+00:00

lock_sock() must be used in process context to be race-free with other lock_sock() callers, for example, tipc_release(). Otherwise using the spinlock directly can't serialize a parallel tipc_release(). As it is blocking, we have to hold the sock refcnt before rhashtable_walk_stop() and release it after rhashtable_walk_start(). Fixes: 07f6c4bc048a ("tipc: convert tipc reference table to use generic rhashtable") Reported-by: Dmitry Vyukov Cc: Ying Xue Cc: Jon Maloy Signed-off-by: Cong Wang Signed-off-by: David S. Miller

tipc: don't assume linear buffer when reading ancillary data

2018-11-18T06:08:02+00:00

The code for reading ancillary data from a received buffer is assuming the buffer is linear. To make this assumption true we have to linearize the buffer before message data is read. Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

Revert "net: simplify sock_poll_wait"

2018-10-23T17:57:06+00:00

This reverts commit dd979b4df817e9976f18fb6f9d134d6bc4a3c317. This broke tcp_poll for SMC fallback: An AF_SMC socket establishes an internal TCP socket for the initial handshake with the remote peer. Whenever the SMC connection can not be established this TCP socket is used as a fallback. All socket operations on the SMC socket are then forwarded to the TCP socket. In case of poll, the file->private_data pointer references the SMC socket because the TCP socket has no file assigned. This causes tcp_poll to wait on the wrong socket. Signed-off-by: Karsten Graul Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-10-13T04:38:46+00:00

Conflicts were easy to resolve using immediate context mostly, except the cls_u32.c one where I simply too the entire HEAD chunk. Signed-off-by: David S. Miller

tipc: queue socket protocol error messages into socket receive buffer

2018-10-11T05:56:07+00:00

In tipc_sk_filter_rcv(), when we detect protocol messages with error we call tipc_sk_conn_proto_rcv() and let it reset the connection and notify the socket by calling sk->sk_state_change(). However, tipc_sk_filter_rcv() may have been called from the function tipc_backlog_rcv(), in which case the socket lock is held and the socket already awake. This means that the sk_state_change() call is ignored and the error notification lost. Now the receive queue will remain empty and the socket sleeps forever. In this commit, we convert the protocol message into a connection abort message and enqueue it into the socket's receive queue. By this addition to the above state change we cover all conditions. Acked-by: Ying Xue Signed-off-by: Parthasarathy Bhuvaragan Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-10-04T04:00:17+00:00

Minor conflict in net/core/rtnetlink.c, David Ahern's bug fix in 'net' overlapped the renaming of a netlink attribute in net-next. Signed-off-by: David S. Miller