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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 0C564C3F2CE for ; Sat, 29 Feb 2020 03:51:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D3A8C246AF for ; Sat, 29 Feb 2020 03:51:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582948299; bh=rr3r6D1CaRDXFXxCtKLzgpjKx+Os8TS7hfd+qs2GWeE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=T6/CrjfdoN3vzlqmBvMt+e2V3Dtg7GSDmHW4S8L9EhC+KsTkkPJ+7s+5/OZQI+ddk OOC0sVDsPn9/bespZw5N2oIKIGe08kar70RPCqn7+Al+quKCMye/50HA+oQ0mx849C 4yPaCUHDmvk6gvGD0yV8xCt+8BLmca63bz03Uyu8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726991AbgB2Dvi (ORCPT ); Fri, 28 Feb 2020 22:51:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:35854 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726627AbgB2Dvi (ORCPT ); Fri, 28 Feb 2020 22:51:38 -0500 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 5A9F2246AE; Sat, 29 Feb 2020 03:51:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582948297; bh=rr3r6D1CaRDXFXxCtKLzgpjKx+Os8TS7hfd+qs2GWeE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=G/SBNwtYegUIIUloqzyCypjRqlIXXCp5RcNKYFOCEtET5a0GKZWb6LGaMwL7a0S93 f/dZmC5ECGHm3BFrhtqzsaErl+avvBcUk85xMc0bb40e733pBXPELOf9Uho9MZfiz+ 9QpNJIFt3/ifiyktg0o7TgLZYEpjORMF8y7o4nL0= Date: Sat, 29 Feb 2020 12:51:31 +0900 From: Masami Hiramatsu To: Masami Hiramatsu Cc: Adrian Hunter , Peter Zijlstra , Ingo Molnar , Steven Rostedt , Borislav Petkov , "H . Peter Anvin" , x86@kernel.org, Mark Rutland , Alexander Shishkin , Mathieu Poirier , Leo Yan , Arnaldo Carvalho de Melo , Jiri Olsa , linux-kernel@vger.kernel.org Subject: Re: [PATCH V3 04/13] kprobes: Add perf ksymbol events for kprobe insn pages Message-Id: <20200229125131.536409697dfa78d4db4e0dfc@kernel.org> In-Reply-To: <20200229001114.91f010e8683418b0dc133837@kernel.org> References: <20200228135125.567-1-adrian.hunter@intel.com> <20200228135125.567-5-adrian.hunter@intel.com> <20200229001114.91f010e8683418b0dc133837@kernel.org> X-Mailer: Sylpheed 3.5.1 (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 Sat, 29 Feb 2020 00:11:14 +0900 Masami Hiramatsu wrote: > On Fri, 28 Feb 2020 15:51:16 +0200 > Adrian Hunter wrote: > > > Symbols are needed for tools to describe instruction addresses. Pages > > allocated for kprobe's purposes need symbols to be created for them. > > Add such symbols to be visible via perf ksymbol events. > > > > Signed-off-by: Adrian Hunter > > --- > > include/uapi/linux/perf_event.h | 5 +++++ > > kernel/kprobes.c | 12 ++++++++++++ > > 2 files changed, 17 insertions(+) > > > > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h > > index bae9e9d2d897..9b38ac04c110 100644 > > --- a/include/uapi/linux/perf_event.h > > +++ b/include/uapi/linux/perf_event.h > > @@ -1031,6 +1031,11 @@ enum perf_event_type { > > enum perf_record_ksymbol_type { > > PERF_RECORD_KSYMBOL_TYPE_UNKNOWN = 0, > > PERF_RECORD_KSYMBOL_TYPE_BPF = 1, > > + /* > > + * Out of line code such as kprobe-replaced instructions or optimized > > + * kprobes. > > + */ > > + PERF_RECORD_KSYMBOL_TYPE_OOL = 2, > > PERF_RECORD_KSYMBOL_TYPE_MAX /* non-ABI */ > > }; > > > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > > index 229d1b596690..f880eb2189c0 100644 > > --- a/kernel/kprobes.c > > +++ b/kernel/kprobes.c > > @@ -35,6 +35,7 @@ > > #include > > #include > > #include > > +#include > > > > #include > > #include > > @@ -184,6 +185,10 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) > > kip->cache = c; > > list_add_rcu(&kip->list, &c->pages); > > slot = kip->insns; > > + > > + /* Record the perf ksymbol register event after adding the page */ > > + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (u64)kip->insns, > > + PAGE_SIZE, false, c->sym); > > out: > > mutex_unlock(&c->mutex); > > return slot; > > @@ -202,6 +207,13 @@ static int collect_one_slot(struct kprobe_insn_page *kip, int idx) > > * next time somebody inserts a probe. > > */ > > if (!list_is_singular(&kip->list)) { > > + /* > > + * Record perf ksymbol unregister event before removing > > + * the page. > > + */ > > + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, > > + (u64)kip->insns, PAGE_SIZE, true, > > + kip->cache->sym); > > list_del_rcu(&kip->list); > > synchronize_rcu(); > > If you think this event should happen after unused the page, > here is the best position to do that. Oops, I've mixed up with another synchronization. Ignore it. This kip should already be safe because all slots are clean here. Acked-by: Masami Hiramatsu Thank you, -- Masami Hiramatsu