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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 2E681C0650E for ; Wed, 3 Jul 2019 14:02:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A767218A6 for ; Wed, 3 Jul 2019 14:02:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727076AbfGCOCI (ORCPT ); Wed, 3 Jul 2019 10:02:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:43420 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725830AbfGCOCI (ORCPT ); Wed, 3 Jul 2019 10:02:08 -0400 Received: from gandalf.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 07A47218A3; Wed, 3 Jul 2019 14:02:06 +0000 (UTC) Date: Wed, 3 Jul 2019 10:02:05 -0400 From: Steven Rostedt To: Mark Rutland Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Masami Hiramatsu , Catalin Marinas Subject: Re: [for-next][PATCH 12/16] kprobes: Initialize kprobes at postcore_initcall Message-ID: <20190703100205.0b58f3bf@gandalf.local.home> In-Reply-To: <20190702165008.GC34718@lakrids.cambridge.arm.com> References: <20190526191828.466305460@goodmis.org> <20190526191848.266163206@goodmis.org> <20190702165008.GC34718@lakrids.cambridge.arm.com> 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 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2 Jul 2019 17:50:09 +0100 Mark Rutland wrote: > On Sun, May 26, 2019 at 03:18:40PM -0400, Steven Rostedt wrote: > > From: Masami Hiramatsu > > > > Initialize kprobes at postcore_initcall level instead of module_init > > since kprobes is not a module, and it depends on only subsystems > > initialized in core_initcall. > > This will allow ftrace kprobe event to add new events when it is > > initializing because ftrace kprobe event is initialized at > > later initcall level. > > > > Link: http://lkml.kernel.org/r/155851394736.15728.13626739508905120098.stgit@devnote2 > > > > Signed-off-by: Masami Hiramatsu > > Signed-off-by: Steven Rostedt (VMware) > > --- > > kernel/kprobes.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > > index b1ea30a5540e..54aaaad00a47 100644 > > --- a/kernel/kprobes.c > > +++ b/kernel/kprobes.c > > @@ -2289,6 +2289,7 @@ static int __init init_kprobes(void) > > init_test_probes(); > > return err; > > } > > +postcore_initcall(init_kprobes); > > As a heads-up, this is causing boot-time failures on arm64. Thanks for the report. > > On arm64 kprobes depends on the BRK handler we register in > debug_traps_init(), which is an arch_initcall. > > As of this change, init_krprobes() calls init_test_probes() before > that's registered, so we end up hitting a BRK before we can handle it. > Would something like this help? -- Steve diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 5471efbeb937..0ca6f53c8505 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2235,6 +2235,8 @@ static struct notifier_block kprobe_module_nb = { extern unsigned long __start_kprobe_blacklist[]; extern unsigned long __stop_kprobe_blacklist[]; +static bool run_kprobe_tests __initdata; + static int __init init_kprobes(void) { int i, err = 0; @@ -2286,11 +2288,18 @@ static int __init init_kprobes(void) kprobes_initialized = (err == 0); if (!err) - init_test_probes(); + run_kprobe_tests = true; return err; } subsys_initcall(init_kprobes); +static int __init run_init_test_probes(void) +{ + if (run_kprobe_tests) + init_test_probes(); +} +module_init(run_init_test_probes); + #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)