From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F4098C5519F for ; Wed, 18 Nov 2020 16:16:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88F09247E0 for ; Wed, 18 Nov 2020 16:16:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="SE9bSGsY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726643AbgKRQPu (ORCPT ); Wed, 18 Nov 2020 11:15:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725874AbgKRQPu (ORCPT ); Wed, 18 Nov 2020 11:15:50 -0500 Received: from mail-qt1-x841.google.com (mail-qt1-x841.google.com [IPv6:2607:f8b0:4864:20::841]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B87B9C0613D4 for ; Wed, 18 Nov 2020 08:15:48 -0800 (PST) Received: by mail-qt1-x841.google.com with SMTP id f93so1964483qtb.10 for ; Wed, 18 Nov 2020 08:15:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=IJE6rXIzbWSElRW1phJDk97yNh0I3oGRFmJIDcQescw=; b=SE9bSGsY7rY7vZ/YERAqp5Aap2XbtOGXi5TykZmuL6lnXFT1tP0Hiy08Y6aKkcx3eU 09nQLfYB9+JCKnQho7Dq7ZUKlVbBCqXx+8li0Ih4MCsdYi9sB8w909NPOxoQd/8X5mFh P5lRTk8JRM+XhkAuWwPLHRv6yWJsn0Y1omjVM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=IJE6rXIzbWSElRW1phJDk97yNh0I3oGRFmJIDcQescw=; b=fOT2tzrNTZNEjsJO30pwndby3nkru85omzh4+VV4RkWy0n6ngpF/ZWqbo3Ob0OgQXW 8nbb5XUHYelzxJpE6XUCc1wQC4VtVCMe9m5Uqr1hPWHBSAzwzmgoTj/KsQ67Vvsn+I8n zqKNDPGoWJVGeXDG91Bf2F62SvNyxeq8WVw0YH4TqEnxpxdf9ybiR+bx30ILpz4MV710 A27HbXD6KQJUbcKAnQdKWCtyra3o6FMW0rQCj8FZ7xY3tOfXq4SN5ciYfO144epi8yTd HgvAzblpSaO3X2JRGKLZRUP2WRhrTlUR73x6XfeFx9igktoO2novYGB/IfRlkMbXHY+M HdPw== X-Gm-Message-State: AOAM532Ejs5qaUMK8GtDODf5II1h0VGCLjI6L5gK8jA8xRhB6PBXACf3 zejFTHng5SewkgYS97pA9+FOlg== X-Google-Smtp-Source: ABdhPJxt4kX6XjIEzA4VfTUA005xth8CjWWyICEF6/zG8klopHRXmTIBquPttrtC6/50FW9tKOVccw== X-Received: by 2002:ac8:6f1c:: with SMTP id g28mr5386731qtv.65.1605716147933; Wed, 18 Nov 2020 08:15:47 -0800 (PST) Received: from joelaf.cam.corp.google.com ([2620:15c:6:411:cad3:ffff:feb3:bd59]) by smtp.gmail.com with ESMTPSA id r62sm17089383qkd.80.2020.11.18.08.15.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Nov 2020 08:15:47 -0800 (PST) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , Josh Triplett , Lai Jiangshan , Mathieu Desnoyers , "Paul E. McKenney" , rcu@vger.kernel.org, Steven Rostedt Subject: [PATCH v2] rcu/segcblist: Add debug checks for segment lengths Date: Wed, 18 Nov 2020 11:15:41 -0500 Message-Id: <20201118161541.3844924-1-joel@joelfernandes.org> X-Mailer: git-send-email 2.29.2.299.gdc1121823c-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org After rcu_do_batch(), add a check for whether the seglen counts went to zero if the list was indeed empty. Signed-off-by: Joel Fernandes (Google) --- v1->v2: Added more debug checks. kernel/rcu/rcu_segcblist.c | 12 ++++++++++++ kernel/rcu/rcu_segcblist.h | 3 +++ kernel/rcu/tree.c | 2 ++ 3 files changed, 17 insertions(+) diff --git a/kernel/rcu/rcu_segcblist.c b/kernel/rcu/rcu_segcblist.c index 5059b6102afe..6e98bb3804f0 100644 --- a/kernel/rcu/rcu_segcblist.c +++ b/kernel/rcu/rcu_segcblist.c @@ -94,6 +94,18 @@ static long rcu_segcblist_get_seglen(struct rcu_segcblist *rsclp, int seg) return READ_ONCE(rsclp->seglen[seg]); } +/* Return number of callbacks in segmented callback list by totalling seglen. */ +long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp) +{ + long len = 0; + int i; + + for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++) + len += rcu_segcblist_get_seglen(rsclp, i); + + return len; +} + /* Set the length of a segment of the rcu_segcblist structure. */ static void rcu_segcblist_set_seglen(struct rcu_segcblist *rsclp, int seg, long v) { diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index cd35c9faaf51..46a42d77f7e1 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -15,6 +15,9 @@ static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp) return READ_ONCE(rclp->len); } +/* Return number of callbacks in segmented callback list by totalling seglen. */ +long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp); + void rcu_cblist_init(struct rcu_cblist *rclp); void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp); void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp, diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index f5b61e10f1de..91e35b521e51 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2553,6 +2553,8 @@ static void rcu_do_batch(struct rcu_data *rdp) WARN_ON_ONCE(count == 0 && !rcu_segcblist_empty(&rdp->cblist)); WARN_ON_ONCE(!IS_ENABLED(CONFIG_RCU_NOCB_CPU) && count != 0 && rcu_segcblist_empty(&rdp->cblist)); + WARN_ON_ONCE(count == 0 && rcu_segcblist_n_segment_cbs(&rdp->cblist) != 0); + WARN_ON_ONCE(count != 0 && rcu_segcblist_n_segment_cbs(&rdp->cblist) == 0); rcu_nocb_unlock_irqrestore(rdp, flags); -- 2.29.2.299.gdc1121823c-goog