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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 2D5E4C433DB for ; Sat, 20 Feb 2021 17:01:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBC6364E38 for ; Sat, 20 Feb 2021 17:01:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229819AbhBTRA6 (ORCPT ); Sat, 20 Feb 2021 12:00:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:38854 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229803AbhBTRA4 (ORCPT ); Sat, 20 Feb 2021 12:00:56 -0500 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 713C764D9A; Sat, 20 Feb 2021 17:00:15 +0000 (UTC) Date: Sat, 20 Feb 2021 12:00:13 -0500 From: Steven Rostedt To: LKML Cc: Ingo Molnar , Andrew Morton , Masami Hiramatsu , "Paul E. McKenney" Subject: [for-next][PATCH] kprobes: Fix to delay the kprobes jump optimization Message-ID: <20210220120013.59c07876@oasis.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.33; 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 Masami Hiramatsu (1): kprobes: Fix to delay the kprobes jump optimization ---- kernel/kprobes.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) --------------------------- commit c85c9a2c6e368dc94907e63babb18a9788e5c9b6 Author: Masami Hiramatsu Date: Thu Feb 18 23:29:23 2021 +0900 kprobes: Fix to delay the kprobes jump optimization Commit 36dadef23fcc ("kprobes: Init kprobes in early_initcall") moved the kprobe setup in early_initcall(), which includes kprobe jump optimization. The kprobes jump optimizer involves synchronize_rcu_tasks() which depends on the ksoftirqd and rcu_spawn_tasks_*(). However, since those are setup in core_initcall(), kprobes jump optimizer can not run at the early_initcall(). To avoid this issue, make the kprobe optimization disabled in the early_initcall() and enables it in subsys_initcall(). Note that non-optimized kprobes is still available after early_initcall(). Only jump optimization is delayed. Link: https://lkml.kernel.org/r/161365856280.719838.12423085451287256713.stgit@devnote2 Fixes: 36dadef23fcc ("kprobes: Init kprobes in early_initcall") Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: RCU Cc: Michael Ellerman Cc: Andrew Morton Cc: Daniel Axtens Cc: Frederic Weisbecker Cc: Neeraj Upadhyay Cc: Joel Fernandes Cc: Michal Hocko Cc: "Theodore Y . Ts'o" Cc: Oleksiy Avramchenko Cc: stable@vger.kernel.org Reported-by: Paul E. McKenney Reported-by: Sebastian Andrzej Siewior Reported-by: Uladzislau Rezki Acked-by: Paul E. McKenney Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index dd1d027455c4..745f08fdd7a6 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -861,7 +861,6 @@ static void try_to_optimize_kprobe(struct kprobe *p) cpus_read_unlock(); } -#ifdef CONFIG_SYSCTL static void optimize_all_kprobes(void) { struct hlist_head *head; @@ -887,6 +886,7 @@ static void optimize_all_kprobes(void) mutex_unlock(&kprobe_mutex); } +#ifdef CONFIG_SYSCTL static void unoptimize_all_kprobes(void) { struct hlist_head *head; @@ -2500,18 +2500,14 @@ static int __init init_kprobes(void) } } -#if defined(CONFIG_OPTPROBES) -#if defined(__ARCH_WANT_KPROBES_INSN_SLOT) - /* Init kprobe_optinsn_slots */ - kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; -#endif - /* By default, kprobes can be optimized */ - kprobes_allow_optimization = true; -#endif - /* By default, kprobes are armed */ kprobes_all_disarmed = false; +#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT) + /* Init kprobe_optinsn_slots for allocation */ + kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE; +#endif + err = arch_init_kprobes(); if (!err) err = register_die_notifier(&kprobe_exceptions_nb); @@ -2526,6 +2522,21 @@ static int __init init_kprobes(void) } early_initcall(init_kprobes); +#if defined(CONFIG_OPTPROBES) +static int __init init_optprobes(void) +{ + /* + * Enable kprobe optimization - this kicks the optimizer which + * depends on synchronize_rcu_tasks() and ksoftirqd, that is + * not spawned in early initcall. So delay the optimization. + */ + optimize_all_kprobes(); + + return 0; +} +subsys_initcall(init_optprobes); +#endif + #ifdef CONFIG_DEBUG_FS static void report_probe(struct seq_file *pi, struct kprobe *p, const char *sym, int offset, char *modname, struct kprobe *pp)