Date: Fri, 23 Jun 2017 21:48:24 -0700 From: Conrad Meyer <cem@freebsd.org> To: Gleb Smirnoff <glebius@freebsd.org> Cc: src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org, Allan Jude <allanjude@freebsd.org> Subject: Re: 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... Message-ID: <CAG6CVpXeLRhJY-rRdbMQTwUPVKqCceFkbiuxxaGNqw7CwuWxUA@mail.gmail.com> In-Reply-To: <201706082130.v58LUY0j095589@repo.freebsd.org> References: <201706082130.v58LUY0j095589@repo.freebsd.org>
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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@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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