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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 DCEADC43441 for ; Wed, 21 Nov 2018 21:17:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9C405206B2 for ; Wed, 21 Nov 2018 21:17:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9C405206B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389815AbeKVHxb (ORCPT ); Thu, 22 Nov 2018 02:53:31 -0500 Received: from ozlabs.org ([203.11.71.1]:46451 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731131AbeKVHxb (ORCPT ); Thu, 22 Nov 2018 02:53:31 -0500 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 430b4l0dG7z9s29; Thu, 22 Nov 2018 08:17:27 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au From: Michael Ellerman To: "Dmitry V. Levin" , Benjamin Herrenschmidt , Paul Mackerras Cc: Oleg Nesterov , Breno Leitao , Andy Lutomirski , Eugene Syromyatnikov , Elvira Khabirova , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] powerpc/ptrace: replace ptrace_report_syscall() with a tracehook call In-Reply-To: <20181119210139.GA8360@altlinux.org> References: <20181116121701.14359da0@akathisia> <87ftw12nyn.fsf@concordia.ellerman.id.au> <20181119210139.GA8360@altlinux.org> Date: Thu, 22 Nov 2018 08:17:25 +1100 Message-ID: <87efbe166y.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dmitry, Thanks for the patch. "Dmitry V. Levin" writes: > From: Elvira Khabirova > > Arch code should use tracehook_*() helpers as documented > in include/linux/tracehook.h, > ptrace_report_syscall() is not expected to be used outside that file. > > Co-authored-by: Dmitry V. Levin > Fixes: 5521eb4bca2d ("powerpc/ptrace: Add support for PTRACE_SYSEMU") > Signed-off-by: Elvira Khabirova > Signed-off-by: Dmitry V. Levin > --- > > v3: add a descriptive comment > v2: explicitly ignore tracehook_report_syscall_entry() return code > > arch/powerpc/kernel/ptrace.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c > index afb819f4ca68..e84220d91bbd 100644 > --- a/arch/powerpc/kernel/ptrace.c > +++ b/arch/powerpc/kernel/ptrace.c > @@ -3266,7 +3266,12 @@ long do_syscall_trace_enter(struct pt_regs *regs) > user_exit(); > > if (test_thread_flag(TIF_SYSCALL_EMU)) { > - ptrace_report_syscall(regs); > + /* > + * A nonzero return code from tracehook_report_syscall_entry() > + * tells us to prevent the syscall execution, but we are not > + * going to execute it anyway. > + */ > + (void) tracehook_report_syscall_entry(regs); Unfortunately the (void) cast doesn't work to suppress the must check warning. arch/powerpc/kernel/ptrace.c:3274:3: error: ignoring return value of 'tracehook_report_syscall_entry', declared with attribute warn_unused_result [-Werror=unused-result] AFAIK we don't have a way to suppress that. I guess we should rewrite it to only call tracehook_report_syscall_entry() once, like x86 does. I'll try and get a patch for that done & tested. cheers 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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 57F06C43441 for ; Wed, 21 Nov 2018 21:19:36 +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 9F099206B2 for ; Wed, 21 Nov 2018 21:19:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F099206B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au 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 430b794hp4zF1nv for ; Thu, 22 Nov 2018 08:19:33 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 430b4l65byzF3Mt for ; Thu, 22 Nov 2018 08:17:27 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 430b4l0dG7z9s29; Thu, 22 Nov 2018 08:17:27 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au From: Michael Ellerman To: "Dmitry V. Levin" , Benjamin Herrenschmidt , Paul Mackerras Subject: Re: [PATCH v3] powerpc/ptrace: replace ptrace_report_syscall() with a tracehook call In-Reply-To: <20181119210139.GA8360@altlinux.org> References: <20181116121701.14359da0@akathisia> <87ftw12nyn.fsf@concordia.ellerman.id.au> <20181119210139.GA8360@altlinux.org> Date: Thu, 22 Nov 2018 08:17:25 +1100 Message-ID: <87efbe166y.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain 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, Oleg Nesterov , Eugene Syromyatnikov , Elvira Khabirova , Andy Lutomirski , Breno Leitao , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi Dmitry, Thanks for the patch. "Dmitry V. Levin" writes: > From: Elvira Khabirova > > Arch code should use tracehook_*() helpers as documented > in include/linux/tracehook.h, > ptrace_report_syscall() is not expected to be used outside that file. > > Co-authored-by: Dmitry V. Levin > Fixes: 5521eb4bca2d ("powerpc/ptrace: Add support for PTRACE_SYSEMU") > Signed-off-by: Elvira Khabirova > Signed-off-by: Dmitry V. Levin > --- > > v3: add a descriptive comment > v2: explicitly ignore tracehook_report_syscall_entry() return code > > arch/powerpc/kernel/ptrace.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c > index afb819f4ca68..e84220d91bbd 100644 > --- a/arch/powerpc/kernel/ptrace.c > +++ b/arch/powerpc/kernel/ptrace.c > @@ -3266,7 +3266,12 @@ long do_syscall_trace_enter(struct pt_regs *regs) > user_exit(); > > if (test_thread_flag(TIF_SYSCALL_EMU)) { > - ptrace_report_syscall(regs); > + /* > + * A nonzero return code from tracehook_report_syscall_entry() > + * tells us to prevent the syscall execution, but we are not > + * going to execute it anyway. > + */ > + (void) tracehook_report_syscall_entry(regs); Unfortunately the (void) cast doesn't work to suppress the must check warning. arch/powerpc/kernel/ptrace.c:3274:3: error: ignoring return value of 'tracehook_report_syscall_entry', declared with attribute warn_unused_result [-Werror=unused-result] AFAIK we don't have a way to suppress that. I guess we should rewrite it to only call tracehook_report_syscall_entry() once, like x86 does. I'll try and get a patch for that done & tested. cheers