From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753553AbcLCP4N (ORCPT ); Sat, 3 Dec 2016 10:56:13 -0500 Received: from mail-lf0-f48.google.com ([209.85.215.48]:34529 "EHLO mail-lf0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752933AbcLCP4M (ORCPT ); Sat, 3 Dec 2016 10:56:12 -0500 MIME-Version: 1.0 In-Reply-To: <20161202210217.GA15126@amd> References: <20161202210217.GA15126@amd> From: Dmitry Vyukov Date: Sat, 3 Dec 2016 16:55:49 +0100 Message-ID: Subject: Re: Unkillable processes due to PTRACE_TRACEME again To: syzkaller Cc: Oleg Nesterov , Denys Vlasenko , jan.kratochvil@redhat.com, palves@redhat.com, Roland McGrath , LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 2, 2016 at 10:02 PM, Pavel Machek wrote: > On Fri 2016-12-02 19:48:40, Dmitry Vyukov wrote: >> Hello, >> >> There was an issue discussed a year ago which leads to >> unkillalble/unwaitable zombie processes due to PTRACE_TRACEME: >> https://groups.google.com/d/msg/syzkaller/uGzwvhlCXAw/E-cfY2ejAgAJ >> and I though it has been fixed by "wait/ptrace: assume __WALL if the >> child is traced": >> https://groups.google.com/d/msg/syzkaller/caeB1ebZWAs/gcbvcM2HDAAJ >> >> I am not on 2caceb3294a78c389b462e7e236a4e744a53a474 (Dec 1). And see > > "Now on"? Yes. >> the same unwaitable zombie processes. > > Well.. I guess git bisect is one option...? I've checked on: commit 91c4e8ea8f05916df0c8a6f383508ac7c9e10dba Author: Oleg Nesterov Date: Mon May 23 16:23:53 2016 -0700 wait: allow sys_waitid() to accept __WNOTHREAD/__WCLONE/__WALL and the program hangs the same way. So it seems that it was just never fixed.