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 E93D7C43613 for ; Fri, 21 Jun 2019 14:41:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFA1C208C3 for ; Fri, 21 Jun 2019 14:41:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561128106; bh=Zx8Cb3sL7YY/8HdLMmq9f5WsUHM/Py3MlcVld2ei5Jo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=WvHLIU6f2kXB+FFpMLAcgnGpxbT6/eVZbKa7qU1v5VCBRGKY8k0+pyMjBa1gk3dQJ 7k7POSrgDQaGWkKmSpMixvwpJNOVQvJpUg0qT73NgWUXWqZRqc5BIt1JuwwjrIZ2QF KQ3rg8714eximfUs3K6MkB3eRiW90uKPBYd87+Uc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726311AbfFUOlp (ORCPT ); Fri, 21 Jun 2019 10:41:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:33756 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726134AbfFUOlo (ORCPT ); Fri, 21 Jun 2019 10:41:44 -0400 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 5A2FF2089E; Fri, 21 Jun 2019 14:41:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561128104; bh=Zx8Cb3sL7YY/8HdLMmq9f5WsUHM/Py3MlcVld2ei5Jo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=z8vJLfX+AQ0JZQfXq307TNp2IDXglTStolUHvFcBpgj1DxYpi4qD386PJeQeLg4TN uND0xqA5PxXmC8Dtf8w1p0JZ6mGe+/8eVM/D6U797f+mt07uppsqnVP9Ly2cXalJGi hptA7WUg5PQJ2Vt63iDJpgVvfw67y8nb/MnSvsRw= Date: Fri, 21 Jun 2019 23:41:40 +0900 From: Masami Hiramatsu To: "Naveen N. Rao" Cc: Michael Ellerman , Steven Rostedt , Ingo Molnar , Nicholas Piggin , , Subject: Re: [PATCH 6/7] kprobes/ftrace: Use ftrace_location() when [dis]arming probes Message-Id: <20190621234140.5604fcd4ae5260b1020deccb@kernel.org> In-Reply-To: <4fedad69107b7fd81b9324315ce4fbf6287e5084.1560868106.git.naveen.n.rao@linux.vnet.ibm.com> References: <4fedad69107b7fd81b9324315ce4fbf6287e5084.1560868106.git.naveen.n.rao@linux.vnet.ibm.com> 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 Tue, 18 Jun 2019 20:17:05 +0530 "Naveen N. Rao" wrote: > Ftrace location could include more than a single instruction in case of > some architectures (powerpc64, for now). In this case, kprobe is > permitted on any of those instructions, and uses ftrace infrastructure > for functioning. > > However, [dis]arm_kprobe_ftrace() uses the kprobe address when setting > up ftrace filter IP. This won't work if the address points to any > instruction apart from the one that has a branch to _mcount(). To > resolve this, have [dis]arm_kprobe_ftrace() use ftrace_function() to > identify the filter IP. This looks good to me. Acked-by: Masami Hiramatsu Thank you! > > Signed-off-by: Naveen N. Rao > --- > kernel/kprobes.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 445337c107e0..282ee704e2d8 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -978,10 +978,10 @@ static int prepare_kprobe(struct kprobe *p) > /* Caller must lock kprobe_mutex */ > static int arm_kprobe_ftrace(struct kprobe *p) > { > + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); > int ret = 0; > > - ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, > - (unsigned long)p->addr, 0, 0); > + ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 0, 0); > if (ret) { > pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n", > p->addr, ret); > @@ -1005,13 +1005,14 @@ static int arm_kprobe_ftrace(struct kprobe *p) > * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental > * empty filter_hash which would undesirably trace all functions. > */ > - ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0); > + ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 1, 0); > return ret; > } > > /* Caller must lock kprobe_mutex */ > static int disarm_kprobe_ftrace(struct kprobe *p) > { > + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); > int ret = 0; > > if (kprobe_ftrace_enabled == 1) { > @@ -1022,8 +1023,7 @@ static int disarm_kprobe_ftrace(struct kprobe *p) > > kprobe_ftrace_enabled--; > > - ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, > - (unsigned long)p->addr, 1, 0); > + ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 1, 0); > WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n", > p->addr, ret); > return ret; > -- > 2.22.0 > -- Masami Hiramatsu 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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 806CDC43613 for ; Fri, 21 Jun 2019 14:47:24 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C5EBD20644 for ; Fri, 21 Jun 2019 14:47:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="z8vJLfX+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C5EBD20644 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45VhNm5XKdzDqf1 for ; Sat, 22 Jun 2019 00:47:20 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=mhiramat@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="z8vJLfX+"; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45VhGL43DrzDqbr for ; Sat, 22 Jun 2019 00:41:46 +1000 (AEST) 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 5A2FF2089E; Fri, 21 Jun 2019 14:41:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561128104; bh=Zx8Cb3sL7YY/8HdLMmq9f5WsUHM/Py3MlcVld2ei5Jo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=z8vJLfX+AQ0JZQfXq307TNp2IDXglTStolUHvFcBpgj1DxYpi4qD386PJeQeLg4TN uND0xqA5PxXmC8Dtf8w1p0JZ6mGe+/8eVM/D6U797f+mt07uppsqnVP9Ly2cXalJGi hptA7WUg5PQJ2Vt63iDJpgVvfw67y8nb/MnSvsRw= Date: Fri, 21 Jun 2019 23:41:40 +0900 From: Masami Hiramatsu To: "Naveen N. Rao" Subject: Re: [PATCH 6/7] kprobes/ftrace: Use ftrace_location() when [dis]arming probes Message-Id: <20190621234140.5604fcd4ae5260b1020deccb@kernel.org> In-Reply-To: <4fedad69107b7fd81b9324315ce4fbf6287e5084.1560868106.git.naveen.n.rao@linux.vnet.ibm.com> References: <4fedad69107b7fd81b9324315ce4fbf6287e5084.1560868106.git.naveen.n.rao@linux.vnet.ibm.com> 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 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, Nicholas Piggin , Steven Rostedt , linuxppc-dev@lists.ozlabs.org, Ingo Molnar Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 18 Jun 2019 20:17:05 +0530 "Naveen N. Rao" wrote: > Ftrace location could include more than a single instruction in case of > some architectures (powerpc64, for now). In this case, kprobe is > permitted on any of those instructions, and uses ftrace infrastructure > for functioning. > > However, [dis]arm_kprobe_ftrace() uses the kprobe address when setting > up ftrace filter IP. This won't work if the address points to any > instruction apart from the one that has a branch to _mcount(). To > resolve this, have [dis]arm_kprobe_ftrace() use ftrace_function() to > identify the filter IP. This looks good to me. Acked-by: Masami Hiramatsu Thank you! > > Signed-off-by: Naveen N. Rao > --- > kernel/kprobes.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 445337c107e0..282ee704e2d8 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -978,10 +978,10 @@ static int prepare_kprobe(struct kprobe *p) > /* Caller must lock kprobe_mutex */ > static int arm_kprobe_ftrace(struct kprobe *p) > { > + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); > int ret = 0; > > - ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, > - (unsigned long)p->addr, 0, 0); > + ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 0, 0); > if (ret) { > pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n", > p->addr, ret); > @@ -1005,13 +1005,14 @@ static int arm_kprobe_ftrace(struct kprobe *p) > * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental > * empty filter_hash which would undesirably trace all functions. > */ > - ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0); > + ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 1, 0); > return ret; > } > > /* Caller must lock kprobe_mutex */ > static int disarm_kprobe_ftrace(struct kprobe *p) > { > + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); > int ret = 0; > > if (kprobe_ftrace_enabled == 1) { > @@ -1022,8 +1023,7 @@ static int disarm_kprobe_ftrace(struct kprobe *p) > > kprobe_ftrace_enabled--; > > - ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, > - (unsigned long)p->addr, 1, 0); > + ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 1, 0); > WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n", > p->addr, ret); > return ret; > -- > 2.22.0 > -- Masami Hiramatsu