From patchwork Fri Aug 4 19:16:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 1817112 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RHb8r0f6Nz1yYl for ; Sat, 5 Aug 2023 05:18:20 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qS0IT-0000Pu-MQ; Fri, 04 Aug 2023 15:17:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qS0IS-0000PH-EM; Fri, 04 Aug 2023 15:17:12 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qS0IR-0006xt-0H; Fri, 04 Aug 2023 15:17:12 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id DBA821845C; Fri, 4 Aug 2023 22:17:11 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id 709CC1B89F; Fri, 4 Aug 2023 22:16:51 +0300 (MSK) Received: (nullmailer pid 1875717 invoked by uid 1000); Fri, 04 Aug 2023 19:16:49 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Richard Henderson , Peter Maydell , Michael Tokarev Subject: [Stable-8.0.4 42/63] util/interval-tree: Use qatomic_set_mb in rb_link_node Date: Fri, 4 Aug 2023 22:16:25 +0300 Message-Id: <20230804191647.1875608-11-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Richard Henderson Ensure that the stores to rb_left and rb_right are complete before inserting the new node into the tree. Otherwise a concurrent reader could see garbage in the new leaf. Cc: qemu-stable@nongnu.org Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson (cherry picked from commit 4c8baa02d36379507afd17bdea87aabe0aa32ed3) Signed-off-by: Michael Tokarev (Mjt: s/qatomic_set_mb/qatomic_mb_set/ for 8.0 - it was renamed later) diff --git a/util/interval-tree.c b/util/interval-tree.c index 5a0ad21b2d..2000cd2935 100644 --- a/util/interval-tree.c +++ b/util/interval-tree.c @@ -128,7 +128,11 @@ static inline void rb_link_node(RBNode *node, RBNode *parent, RBNode **rb_link) node->rb_parent_color = (uintptr_t)parent; node->rb_left = node->rb_right = NULL; - qatomic_set(rb_link, node); + /* + * Ensure that node is initialized before insertion, + * as viewed by a concurrent search. + */ + qatomic_mb_set(rb_link, node); } static RBNode *rb_next(RBNode *node)