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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 1EE82C43441 for ; Tue, 27 Nov 2018 16:23:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E24BE2086B for ; Tue, 27 Nov 2018 16:23:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E24BE2086B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 S1730885AbeK1DVy (ORCPT ); Tue, 27 Nov 2018 22:21:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34856 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726510AbeK1DVx (ORCPT ); Tue, 27 Nov 2018 22:21:53 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 30C1D3001FFB; Tue, 27 Nov 2018 16:23:29 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.12]) by smtp.corp.redhat.com (Postfix) with SMTP id 2D9DE105705A; Tue, 27 Nov 2018 16:23:28 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 27 Nov 2018 17:23:28 +0100 (CET) Date: Tue, 27 Nov 2018 17:23:27 +0100 From: Oleg Nesterov To: Andrei Vagin Cc: linux-kernel@vger.kernel.org, "Eric W. Biederman" , Andrew Morton Subject: Re: [PATCH] ptrace: take into account saved_sigmask in PTRACE_{GET,SET}SIGMASK Message-ID: <20181127162326.GB13284@redhat.com> References: <20181120060616.6043-1-avagin@gmail.com> <20181122114751.GA28270@redhat.com> <20181127063758.GA10422@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20181127063758.GA10422@gmail.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Tue, 27 Nov 2018 16:23:29 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/26, Andrei Vagin wrote: > > > IOW, could you please explain how PTRACE_SETSIGMASK should be used, and why > > it doesn't do something like > > > > CRIU uses PTRACE_SETSIGMASK when it injects a parasite code into a > target process. In this case, we have to be sure that when the process > is resumed by PTRACE_CONT, it will not start handling signals and > executing signal handlers. So iiuc CRUI uses PTRACE_SETSIGMASK to block all signals, run the parasite code, then restore the original sigmask. Assuming that CRIU also turns ERESTARTNOHAND into syscall-restart (I think it does ;) everything looks correct... OK, I think the patch is fine. Oleg.