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 53779C43458 for ; Fri, 10 Jul 2026 12:54:33 +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=7MUEx1KjIzG7NovESSu8NnA5XsIPl5lb4+41BSLUucQ=; b=h48Xb6jFnbb9Gn upLXl6rCS1jgHhnyHBHrJTxha8wDCrUnmkSQU9cibvyc4zRQTMTuLvYqzl2qXK2rSkpUj2thrMdLC HwnY7IgcIAkJCqJ8qjLt6tQ7vGimq54xse0ECqx+qL5xtVUTZMBTvfynAju+CvK8snVx1y84A+0D1 4mUUF5OeUuSqL/V8a0/Keln8zh3kGAKJtpE1w5pEt6T+qIokRutRgOLpAGjCZB09CsCmRKx3RA/D6 V4zhehForPwQP8qZB+b0IT1AeAq0X/C0+pMWEy6ZXHhclF3TFWFTiWks0xmJqybNiqZQAT3qy8p7n Er89vGQ+XPaK7DuQOSJA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wiAkS-00000004xK0-1kEE; Fri, 10 Jul 2026 12:54:32 +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 1wiAkP-00000004xJM-1yBC for linux-snps-arc@lists.infradead.org; Fri, 10 Jul 2026 12:54:31 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783688068; 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=XTxMckJ71iKdcnC625lbZ9WJQgTp+gyXuVTaxsSZYeA=; b=D7RWQbQcORHkEeyQTPrD8OZ4j/7LY3DRAmztSzhxkPwmTNDZZZc0mgNiEpeJ/Tuq9UGORu JhNKaJ0LiS6l6wtERiT3xS0waJ+fZLu7w902zxq61vAhE+5mPNywoXey0f/erlDhgGqGUL pCAcg22Lrie/e5B5qIYSauuMF8Dkc74= Received: from mx-prod-mc-08.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-640-duefXCb_NOaqJcpTJsNlCw-1; Fri, 10 Jul 2026 08:53:17 -0400 X-MC-Unique: duefXCb_NOaqJcpTJsNlCw-1 X-Mimecast-MFC-AGG-ID: duefXCb_NOaqJcpTJsNlCw_1783687991 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AAE061801379; Fri, 10 Jul 2026 12:53:07 +0000 (UTC) Received: from fedora (unknown [10.44.49.164]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 8AEF2180029C; Fri, 10 Jul 2026 12:52:47 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 10 Jul 2026 14:53:07 +0200 (CEST) Date: Fri, 10 Jul 2026 14:52:40 +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 3.4.1 on 10.30.177.93 X-Mimecast-MFC-PROC-ID: WhnCUEM5aA8rpag38VbaH3f-V5diAWCs65FpNqbDIPg_1783687991 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_055429_571139_F0ED68CF X-CRM114-Status: GOOD ( 23.35 ) 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 Fri, Jul 10, 2026 at 01:40:43PM +0200, Oleg Nesterov wrote: > > > > 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 su= pport > > 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. > > Or it could be documented that setting the return value has to be done > in the exit trace, and that would than work on any architecture AFAICT. Well, ptrace users know the problem. And this what they have to do currently. > With ppc and s390 using the same register for the syscall number and > syscall return value it's very much impossible to poke the return value > on entry into a register using the generic register access function. As > of now there is no place to store the value ot of the return value > outside of the registers, either. I know nothing about ppc and s390. Can't comment right now. > And the current PTRACE_SET_SYSCALL_INFO indeed sets the syscall nr and > arguments on entry and the syscall return value on exit, that > disctincion is implemented. > > Not sure how the patchset you point out is relevant, it only adds > changes in the exit case. No. It allows to skip-and-set-retval on PTRACE_EVENT_SECCOMP. But ENTRY -> EXIT transition is not yet allowed due to the problems above. Oleg. _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc