svn commit: r319722 - in head: sys/cam/ctl sys/dev/iscsi sys/kern sys/netgraph sys/netgraph/bluetooth/socket sys/netinet sys/ofed/drivers/infiniband/core sys/ofed/drivers/infiniband/ulp/sdp sys/rpc...
Conrad Meyer
cem at freebsd.org
Sat Jun 24 04:48:33 UTC 2017
Hi Gleb,
We suspect this revision has broken setsockopt(SO_SNDBUF), etc., on
listen sockets, as used by e.g. nginx.
Example backtrace: http://imgur.com/a/fj5JQ
The proposed mechanism is the destroyed snd/rcv sockbufs (and
associated locks) as part of solisten_proto().
Best,
Conrad
On Thu, Jun 8, 2017 at 2:30 PM, Gleb Smirnoff <glebius at freebsd.org> wrote:
> Author: glebius
> Date: Thu Jun 8 21:30:34 2017
> New Revision: 319722
> URL: https://svnweb.freebsd.org/changeset/base/319722
>
> Log:
> Listening sockets improvements.
>
> o Separate fields of struct socket that belong to listening from
> fields that belong to normal dataflow, and unionize them. This
> shrinks the structure a bit.
> - Take out selinfo's from the socket buffers into the socket. The
> first reason is to support braindamaged scenario when a socket is
> added to kevent(2) and then listen(2) is cast on it. The second
> reason is that there is future plan to make socket buffers pluggable,
> so that for a dataflow socket a socket buffer can be changed, and
> in this case we also want to keep same selinfos through the lifetime
> of a socket.
> - Remove struct struct so_accf. Since now listening stuff no longer
> affects struct socket size, just move its fields into listening part
> of the union.
> - Provide sol_upcall field and enforce that so_upcall_set() may be called
> only on a dataflow socket, which has buffers, and for listening sockets
> provide solisten_upcall_set().
>
> o Remove ACCEPT_LOCK() global.
> - Add a mutex to socket, to be used instead of socket buffer lock to lock
> fields of struct socket that don't belong to a socket buffer.
> - Allow to acquire two socket locks, but the first one must belong to a
> listening socket.
> - Make soref()/sorele() to use atomic(9). This allows in some situations
> to do soref() without owning socket lock. There is place for improvement
> here, it is possible to make sorele() also to lock optionally.
> - Most protocols aren't touched by this change, except UNIX local sockets.
> See below for more information.
>
> o Reduce copy-and-paste in kernel modules that accept connections from
> listening sockets: provide function solisten_dequeue(), and use it in
> the following modules: ctl(4), iscsi(4), ng_btsocket(4), ng_ksocket(4),
> infiniband, rpc.
>
> o UNIX local sockets.
> - Removal of ACCEPT_LOCK() global uncovered several races in the UNIX
> local sockets. Most races exist around spawning a new socket, when we
> are connecting to a local listening socket. To cover them, we need to
> hold locks on both PCBs when spawning a third one. This means holding
> them across sonewconn(). This creates a LOR between pcb locks and
> unp_list_lock.
> - To fix the new LOR, abandon the global unp_list_lock in favor of global
> unp_link_lock. Indeed, separating these two locks didn't provide us any
> extra parralelism in the UNIX sockets.
> - Now call into uipc_attach() may happen with unp_link_lock hold if, we
> are accepting, or without unp_link_lock in case if we are just creating
> a socket.
> - Another problem in UNIX sockets is that uipc_close() basicly did nothing
> for a listening socket. The vnode remained opened for connections. This
> is fixed by removing vnode in uipc_close(). Maybe the right way would be
> to do it for all sockets (not only listening), simply move the vnode
> teardown from uipc_detach() to uipc_close()?
>
> Sponsored by: Netflix
> Differential Revision: https://reviews.freebsd.org/D9770
>
> Modified:
> head/sys/cam/ctl/ctl_ha.c
> head/sys/dev/iscsi/icl_soft_proxy.c
> head/sys/kern/sys_socket.c
> head/sys/kern/uipc_accf.c
> head/sys/kern/uipc_debug.c
> head/sys/kern/uipc_sockbuf.c
> head/sys/kern/uipc_socket.c
> head/sys/kern/uipc_syscalls.c
> head/sys/kern/uipc_usrreq.c
> head/sys/netgraph/bluetooth/socket/ng_btsocket_l2cap.c
> head/sys/netgraph/bluetooth/socket/ng_btsocket_rfcomm.c
> head/sys/netgraph/bluetooth/socket/ng_btsocket_sco.c
> head/sys/netgraph/ng_ksocket.c
> head/sys/netinet/sctp_input.c
> head/sys/netinet/sctp_syscalls.c
> head/sys/netinet/sctp_sysctl.c
> head/sys/netinet/sctp_usrreq.c
> head/sys/netinet/tcp_subr.c
> head/sys/netinet/tcp_syncache.c
> head/sys/netinet/tcp_timewait.c
> head/sys/ofed/drivers/infiniband/core/iwcm.c
> head/sys/ofed/drivers/infiniband/ulp/sdp/sdp_main.c
> head/sys/rpc/svc_vc.c
> head/sys/sys/sockbuf.h
> head/sys/sys/socket.h
> head/sys/sys/socketvar.h
> head/usr.bin/netstat/inet.c
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