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=-13.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham 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 11E6FC4363D for ; Wed, 30 Sep 2020 23:54:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB5AF20780 for ; Wed, 30 Sep 2020 23:54:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731733AbgI3XyC (ORCPT ); Wed, 30 Sep 2020 19:54:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:45086 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730192AbgI3XyB (ORCPT ); Wed, 30 Sep 2020 19:54:01 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B9DEB206FA; Wed, 30 Sep 2020 23:54:00 +0000 (UTC) Date: Wed, 30 Sep 2020 19:53:59 -0400 From: Steven Rostedt To: Linus Torvalds Cc: LKML , Ingo Molnar , Andrew Morton Subject: [GIT PULL] tracing: A couple of fixes Message-ID: <20200930195359.01d9f770@oasis.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus, Two tracing fixes: - Fix temp buffer accounting that caused a WARNING for ftrace_dump_on_opps() - Move the recursion check in one of the function callback helpers to the beginning of the function, as if the rcu_is_watching() gets traced, it will cause a recursive loop that will crash the kernel. Please pull the latest trace-v5.9-rc6 tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-v5.9-rc6 Tag SHA1: 87d55eca1585b1bd70fe7de33cd5ea2957628027 Head SHA1: b40341fad6cc2daa195f8090fd3348f18fff640a Steven Rostedt (VMware) (2): tracing: Fix trace_find_next_entry() accounting of temp buffer size ftrace: Move RCU is watching check after recursion check ---- kernel/trace/ftrace.c | 6 ++---- kernel/trace/trace.c | 10 ++++++---- 2 files changed, 8 insertions(+), 8 deletions(-) --------------------------- diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 603255f5f085..541453927c82 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6993,16 +6993,14 @@ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, { int bit; - if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching()) - return; - bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); if (bit < 0) return; preempt_disable_notrace(); - op->func(ip, parent_ip, op, regs); + if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) + op->func(ip, parent_ip, op, regs); preempt_enable_notrace(); trace_clear_recursion(bit); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2a7c26345e83..d3e5de717df2 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3546,13 +3546,15 @@ struct trace_entry *trace_find_next_entry(struct trace_iterator *iter, if (iter->ent && iter->ent != iter->temp) { if ((!iter->temp || iter->temp_size < iter->ent_size) && !WARN_ON_ONCE(iter->temp == static_temp_buf)) { - kfree(iter->temp); - iter->temp = kmalloc(iter->ent_size, GFP_KERNEL); - if (!iter->temp) + void *temp; + temp = kmalloc(iter->ent_size, GFP_KERNEL); + if (!temp) return NULL; + kfree(iter->temp); + iter->temp = temp; + iter->temp_size = iter->ent_size; } memcpy(iter->temp, iter->ent, iter->ent_size); - iter->temp_size = iter->ent_size; iter->ent = iter->temp; } entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);