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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 705FBC43458 for ; Fri, 10 Jul 2026 11:41:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=k1ZNJddLBLGHxQ2BhyDeCScHR+eMYAOUaS4HGTf6Bi0=; b=h3fYV/RnyJdKw8 JwUQOg0AohX3HfvvdSzovDW99sizSa2N9eEaqykDZZLz9/w3tyub4/gMUUTWg3xzWn6FltkztnpDL JNefU/l9v1Ef1XRz09giprbBOo7PkH5RVTchyUEm7p0sZOPFW/M8oaQksMyQV6UfFsmILoapuaE73 iLl1ACG6NPXZqRublOQtBzNcgpEeISjPlLvBb5VPC4S7chY7uVUuDPCPWx2MVCybxzakZgkO+r1PY 6kuKZdaRyaOZz1k/vNgvMR/eOfFIIFu4LON8vz3yyrNsW9gSpzrse4gX1umPhV1I5ca9HjiheT8NW tkfJUjrvVWr7KKLSDZcQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wi9bc-00000004qHu-47HR; Fri, 10 Jul 2026 11:41:20 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wi9bZ-00000004qGF-03tf for linux-snps-arc@lists.infradead.org; Fri, 10 Jul 2026 11:41:19 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783683675; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=okIzKFIsL/4R4vmkR+TFByt5pFrNsTBzPM+Bl8mNt+c=; b=irYNBYOPH3KA1tNtJoaP4cvoz+B4M303DtxZQ82Zy1nT4jNi1jBQ1cNlX7qRpQzo5ucvCv bXP40t5WaIPxHZFxiOXUc8yTujzCHnZGQZOl0G3k75eLea4WTQR0T20/47j1mroE4fMJNn DfCHbiEafjfiBBByO/vWPBblfZi4zYk= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-21-qfsr_rx-O6mPQrP7hF_qjQ-1; Fri, 10 Jul 2026 07:41:12 -0400 X-MC-Unique: qfsr_rx-O6mPQrP7hF_qjQ-1 X-Mimecast-MFC-AGG-ID: qfsr_rx-O6mPQrP7hF_qjQ_1783683667 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B188F1800844; Fri, 10 Jul 2026 11:41:03 +0000 (UTC) Received: from fedora (unknown [10.44.49.164]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 8F127195419F; Fri, 10 Jul 2026 11:40:45 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 10 Jul 2026 13:41:03 +0200 (CEST) Date: Fri, 10 Jul 2026 13:40:43 +0200 From: Oleg Nesterov To: Michal =?iso-8859-1?Q?Such=E1nek?= Cc: Thomas Gleixner , LKML , Peter Zijlstra , Michael Ellerman , Shrikanth Hegde , linuxppc-dev@lists.ozlabs.org, Kees Cook , Huacai Chen , loongarch@lists.linux.dev, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Sven Schnelle , linux-s390@vger.kernel.org, x86@kernel.org, Mark Rutland , Jinjie Ruan , Andy Lutomirski , Richard Henderson , Russell King , Catalin Marinas , Guo Ren , Geert Uytterhoeven , Thomas Bogendoerfer , Helge Deller , Yoshinori Sato , Richard Weinberger , Chris Zankel , linux-arm-kernel@lists.infradead.org, linux-alpha@vger.kernel.org, linux-csky@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-um@lists.infradead.org, Arnd Bergmann , Vineet Gupta , Will Deacon , Brian Cain , Michal Simek , Dinh Nguyen , "David S. Miller" , Andreas Larsson , linux-snps-arc@lists.infradead.org, linux-hexagon@vger.kernel.org, linux-openrisc@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org Subject: Re: [patch 13/18] entry: Make trace_syscall_enter() return type bool Message-ID: References: <20260707181957.433213175@kernel.org> <20260707190254.338083894@kernel.org> <87se5tqkyp.ffs@fw13> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Mimecast-MFC-PROC-ID: VQA8P82cGgdhVqbv1CZOODObge1cDUvSw2JQ9taYdIU_1783683667 X-Mimecast-Originator: redhat.com Content-Disposition: inline X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260710_044117_125501_C14F12F9 X-CRM114-Status: GOOD ( 18.76 ) X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org On 07/10, Michal Such=E1nek wrote: > > On Wed, Jul 08, 2026 at 10:34:38PM +0200, Thomas Gleixner wrote: > > > > 1) The set in stone rule is that if the entry code returns -1L as the > > syscall number then the architecture code has to skip the syscall > > invocation _and_ is not supposed to change the return value. > > Which stone? > > Pics or it did not happen. > > > > > 2) There is no guarantee and never has been that any of the involved > > mechanisms (ptrace, seccomp, tracing) will change the return value > > when it sets the syscall number to -1L. > > For ptrace to correctly emulate a syscall it needs to set the syscall nr > to an invalid value on entry, and the desired result if the syscall on > exit AFAICT. I can only say that ptrace users do want to skip the syscall and set the return value on entry. See [PATCH v5 1/2] ptrace: add PTRACE_SET_SYSCALL_INFO syscall skipping support https://lore.kernel.org/all/20260709100949.94345-2-renzo@cs.unibo.it/ The changelog explains that currently this doesn't work because among the arches which define HAVE_ARCH_TRACEHOOK (at least) arch/mips is broken in this regard. Oleg. _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc