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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5E66DC4332B for ; Sat, 4 Apr 2020 16:01:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32A35206D4 for ; Sat, 4 Apr 2020 16:01:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="N6pSD8rj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726331AbgDDQBt (ORCPT ); Sat, 4 Apr 2020 12:01:49 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:59895 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726229AbgDDQBt (ORCPT ); Sat, 4 Apr 2020 12:01:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1586016107; 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: in-reply-to:in-reply-to:references:references; bh=FUdF7iY9SS4OEmK+NSy6HOWdmAoXBxog9A83yLakpIU=; b=N6pSD8rjDqkXLc4GCSkwKuyhxQbMPzLn/DpMrjSqeacBuf9hfkOUSkfLGZMoOj/f1Xrz33 rvAlZkq5rnLpgU1MswcktZ9uXZI93ip/4p3ZWuPudqMxVt2plgqnzsvDNXr8ba70wM1zpJ 6qNsJrr8b6oKqvqzCn5Y2l2X2NsLF5E= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-398-BLP3HdZDO0Sr1HutAcntrQ-1; Sat, 04 Apr 2020 12:01:45 -0400 X-MC-Unique: BLP3HdZDO0Sr1HutAcntrQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1D07218A6EC1; Sat, 4 Apr 2020 16:01:08 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.192.53]) by smtp.corp.redhat.com (Postfix) with SMTP id 2443F5C541; Sat, 4 Apr 2020 16:01:01 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Sat, 4 Apr 2020 18:01:07 +0200 (CEST) Date: Sat, 4 Apr 2020 18:01:00 +0200 From: Oleg Nesterov To: Nick Desaulniers Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, Peter Zijlstra , clang-built-linux@googlegroups.com, Linus Torvalds , "H. Peter Anvin" , x86@kernel.org, Al Viro , Sebastian Andrzej Siewior , Andy Lutomirski , Sami Tolvanen , Marco Elver , Brian Gerst , Arnd Bergmann , Andrew Morton , "Eric W. Biederman" , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] x86: signal: move save_altstack_ex out of generic headers Message-ID: <20200404160100.GB26298@redhat.com> References: <20200324220830.110002-1-ndesaulniers@google.com> <20200403231611.81444-1-ndesaulniers@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200403231611.81444-1-ndesaulniers@google.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/03, Nick Desaulniers wrote: > > --- a/arch/x86/kernel/signal.c > +++ b/arch/x86/kernel/signal.c > @@ -416,6 +416,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, > return 0; > Efault: > user_access_end(); > + reset_altstack(); > return -EFAULT; > } > #else /* !CONFIG_X86_32 */ > @@ -507,6 +508,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, > > Efault: > user_access_end(); > + reset_altstack(); > return -EFAULT; > } I must have missed something, but this looks just wrong. reset_altstack() should be called when __setup_rt_frame() (and unsafe_save_altstack() in particular) succeeds, not when it fails. Nevermind, Al has already suggested to use signal_delivered()... Oleg.