From owner-svn-src-all@freebsd.org Thu May 14 20:17:10 2020 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 017902DDB85; Thu, 14 May 2020 20:17:10 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49NN9x6CLHz3MXk; Thu, 14 May 2020 20:17:09 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id D04EC18B35; Thu, 14 May 2020 20:17:09 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 04EKH9aZ071967; Thu, 14 May 2020 20:17:09 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 04EKH9pQ071966; Thu, 14 May 2020 20:17:09 GMT (envelope-from kib@FreeBSD.org) Message-Id: <202005142017.04EKH9pQ071966@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Thu, 14 May 2020 20:17:09 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r361056 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: kib X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 361056 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 May 2020 20:17:10 -0000 Author: kib Date: Thu May 14 20:17:09 2020 New Revision: 361056 URL: https://svnweb.freebsd.org/changeset/base/361056 Log: Fix r361037. Reorder flag manipulations and use barrier to ensure that the program order is followed by compiler and CPU, for unlocked reader of so_state. In collaboration with: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D24842 Modified: head/sys/kern/uipc_socket.c Modified: head/sys/kern/uipc_socket.c ============================================================================== --- head/sys/kern/uipc_socket.c Thu May 14 20:07:02 2020 (r361055) +++ head/sys/kern/uipc_socket.c Thu May 14 20:17:09 2020 (r361056) @@ -4016,8 +4016,17 @@ soisdisconnected(struct socket *so) { SOCK_LOCK(so); - 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); if (!SOLISTENING(so)) { SOCK_UNLOCK(so);