From owner-svn-src-all@freebsd.org Tue Oct 13 18:28:49 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 7AB32448088; Tue, 13 Oct 2020 18:28:49 +0000 (UTC) (envelope-from tychon@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) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 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 4C9kZn2fXtz42r3; Tue, 13 Oct 2020 18:28:49 +0000 (UTC) (envelope-from tychon@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 3E8BB2166F; Tue, 13 Oct 2020 18:28:49 +0000 (UTC) (envelope-from tychon@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 09DISn34052542; Tue, 13 Oct 2020 18:28:49 GMT (envelope-from tychon@FreeBSD.org) Received: (from tychon@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 09DISnmc052541; Tue, 13 Oct 2020 18:28:49 GMT (envelope-from tychon@FreeBSD.org) Message-Id: <202010131828.09DISnmc052541@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: tychon set sender to tychon@FreeBSD.org using -f From: Tycho Nightingale Date: Tue, 13 Oct 2020 18:28:49 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r366678 - head/sys/amd64/amd64 X-SVN-Group: head X-SVN-Commit-Author: tychon X-SVN-Commit-Paths: head/sys/amd64/amd64 X-SVN-Commit-Revision: 366678 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: Tue, 13 Oct 2020 18:28:49 -0000 Author: tychon Date: Tue Oct 13 18:28:48 2020 New Revision: 366678 URL: https://svnweb.freebsd.org/changeset/base/366678 Log: eliminate possible race in parallel TLB shootdown IPI On the target side TLB shootdown IPI handler, prevent the compiler from performing a forward store optimization which may mask a subsequent update to the scoreboard by the initiator. Reported by: Max Laier, Anton Rang Discussed with: kib Sponsored by: Dell EMC Isilon Modified: head/sys/amd64/amd64/mp_machdep.c Modified: head/sys/amd64/amd64/mp_machdep.c ============================================================================== --- head/sys/amd64/amd64/mp_machdep.c Tue Oct 13 18:04:19 2020 (r366677) +++ head/sys/amd64/amd64/mp_machdep.c Tue Oct 13 18:28:48 2020 (r366678) @@ -1094,7 +1094,7 @@ invlop_handler(void) for (;;) { for (initiator_cpu_id = 0; initiator_cpu_id <= mp_maxid; initiator_cpu_id++) { - if (scoreboard[initiator_cpu_id] == 0) + if (atomic_load_int(&scoreboard[initiator_cpu_id]) == 0) break; } if (initiator_cpu_id > mp_maxid)