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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 A9BEBC352A5 for ; Mon, 10 Feb 2020 14:36:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E15D20873 for ; Mon, 10 Feb 2020 14:36:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="jkUs4hzN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727973AbgBJOgc (ORCPT ); Mon, 10 Feb 2020 09:36:32 -0500 Received: from mail-qv1-f68.google.com ([209.85.219.68]:44880 "EHLO mail-qv1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727598AbgBJOgc (ORCPT ); Mon, 10 Feb 2020 09:36:32 -0500 Received: by mail-qv1-f68.google.com with SMTP id n8so3234900qvg.11 for ; Mon, 10 Feb 2020 06:36:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=sw8aLoMN7edQi9tCuvhNl/iVTODc75PkGH73eAqI96U=; b=jkUs4hzNPVCxprNaYv/MX6zJKcph8mNHMTtg4GPspg617lRSe8FqvFZb+o6DjOVQrr 37PLeSeLutY7XJ9bF9R8p8fkpRVR1+dbJ/xoFkZpdtBhUjgQ8XP3/erYccm80CSIsQOt HdrE0hqNGzxMN1RMnvutju/NJGpV26qWRmjJE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=sw8aLoMN7edQi9tCuvhNl/iVTODc75PkGH73eAqI96U=; b=GZXvwHtcbScpDKEf0BVO1E2gSTu3952LhQx7OktedyQ5gqoH0Vh7ZScruIUzKsfAiO k2pKFBrblGOXYPFjA8cfBnKAsSRCigZHGAx+qdtl0vrZFhwyxSlF3FPYiH52Y6arjJiu gMvBzaaItBk67WRaWTc8s5GbbQ2wTYgCpm2pILfwC97C+NXujhG/YGZ/LkJa5AvO2Fy3 ABLRk700kVVCx4E+kuzI9cknSRzjmBsvyS3Owvy2xRlSaCK+G8XebL1j6zWd0a9MAOj1 XJa5NAJJ2q8qSLpXBKb+JDPcHPvxUX1wtKwvo++tWOcUOfwnru6cfVzMrBtIMEQXjoMP 4ijQ== X-Gm-Message-State: APjAAAXuSXFHrGqaWV0TK5hK16NpRoYK+J4ECF+vFENN0sLiPA1qDDwl zMekwtkdZCs4ptySVUacTVSKmptefsGNQBQMz7IQpw== X-Google-Smtp-Source: APXvYqwRHxH3WegeUNyf9KYF23HojSS4aZrwxB1WWUB6IVN0BNlAXwRaNtfCrRRaOByrQcK4G1XSGw2HvfkGNzkvMhQ= X-Received: by 2002:a0c:f685:: with SMTP id p5mr10354179qvn.44.1581345391131; Mon, 10 Feb 2020 06:36:31 -0800 (PST) MIME-Version: 1.0 References: <20200210122423.695146547@linuxfoundation.org> <20200210122438.674498788@linuxfoundation.org> In-Reply-To: <20200210122438.674498788@linuxfoundation.org> From: Joel Fernandes Date: Mon, 10 Feb 2020 06:36:20 -0800 Message-ID: Subject: Re: [PATCH 5.5 150/367] tracing: Annotate ftrace_graph_hash pointer with __rcu To: Amol Grover Cc: LKML , Greg Kroah-Hartman , stable , "Steven Rostedt (VMware)" , Sasha Levin Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 10, 2020 at 4:40 AM Greg Kroah-Hartman wrote: > > From: Amol Grover > > [ Upstream commit 24a9729f831462b1d9d61dc85ecc91c59037243f ] Amol, can you send a follow-up patch to annotate ftrace_graph_notrace_hash as well? - Joel > > Fix following instances of sparse error > kernel/trace/ftrace.c:5664:29: error: incompatible types in comparison > kernel/trace/ftrace.c:5785:21: error: incompatible types in comparison > kernel/trace/ftrace.c:5864:36: error: incompatible types in comparison > kernel/trace/ftrace.c:5866:25: error: incompatible types in comparison > > Use rcu_dereference_protected to access the __rcu annotated pointer. > > Link: http://lkml.kernel.org/r/20200201072703.17330-1-frextrite@gmail.com > > Reviewed-by: Joel Fernandes (Google) > Signed-off-by: Amol Grover > Signed-off-by: Steven Rostedt (VMware) > Signed-off-by: Sasha Levin > --- > kernel/trace/ftrace.c | 2 +- > kernel/trace/trace.h | 9 ++++++--- > 2 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index 9bf1f2cd515ef..959ded08dc13f 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -5596,7 +5596,7 @@ static const struct file_operations ftrace_notrace_fops = { > > static DEFINE_MUTEX(graph_lock); > > -struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH; > +struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH; > struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH; > > enum graph_filter_type { > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 63bf60f793987..97dad33260208 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -950,22 +950,25 @@ extern void __trace_graph_return(struct trace_array *tr, > unsigned long flags, int pc); > > #ifdef CONFIG_DYNAMIC_FTRACE > -extern struct ftrace_hash *ftrace_graph_hash; > +extern struct ftrace_hash __rcu *ftrace_graph_hash; > extern struct ftrace_hash *ftrace_graph_notrace_hash; > > static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace) > { > unsigned long addr = trace->func; > int ret = 0; > + struct ftrace_hash *hash; > > preempt_disable_notrace(); > > - if (ftrace_hash_empty(ftrace_graph_hash)) { > + hash = rcu_dereference_protected(ftrace_graph_hash, !preemptible()); > + > + if (ftrace_hash_empty(hash)) { > ret = 1; > goto out; > } > > - if (ftrace_lookup_ip(ftrace_graph_hash, addr)) { > + if (ftrace_lookup_ip(hash, addr)) { > > /* > * This needs to be cleared on the return functions > -- > 2.20.1 > > >