Date: Thu, 21 May 2020 11:14:13 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r361328 - stable/11/sys/kern Message-ID: <202005211114.04LBEDEf012487@repo.freebsd.org>
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Author: kib Date: Thu May 21 11:14:13 2020 New Revision: 361328 URL: https://svnweb.freebsd.org/changeset/base/361328 Log: MFC r361037, r361056: Fix spurious ENOTCONN from closed unix domain socket other' side. Modified: stable/11/sys/kern/uipc_socket.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/kern/uipc_socket.c ============================================================================== --- stable/11/sys/kern/uipc_socket.c Thu May 21 11:12:27 2020 (r361327) +++ stable/11/sys/kern/uipc_socket.c Thu May 21 11:14:13 2020 (r361328) @@ -1565,8 +1565,9 @@ restart: m = so->so_rcv.sb_mb; goto dontblock; } - if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0 && - (so->so_proto->pr_flags & PR_CONNREQUIRED)) { + if ((so->so_state & (SS_ISCONNECTING | SS_ISCONNECTED | + SS_ISDISCONNECTING | SS_ISDISCONNECTED)) == 0 && + (so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) { SOCKBUF_UNLOCK(&so->so_rcv); error = ENOTCONN; goto release; @@ -3516,8 +3517,17 @@ soisdisconnected(struct socket *so) * SOCKBUF_LOCK(&so->so_rcv) are the same. */ SOCKBUF_LOCK(&so->so_rcv); - so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); + + /* + * There is at least one reader of so_state that does not + * acquire socket lock, namely soreceive_generic(). Ensure + * that it never sees all flags that track connection status + * cleared, by ordering the update with a barrier semantic of + * our release thread fence. + */ so->so_state |= SS_ISDISCONNECTED; + atomic_thread_fence_rel(); + so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING); socantrcvmore_locked(so); SOCKBUF_LOCK(&so->so_snd); sbdrop_locked(&so->so_snd, sbused(&so->so_snd));
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