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 3E92EC169C4 for ; Sun, 3 Feb 2019 15:21:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1079520821 for ; Sun, 3 Feb 2019 15:21:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728061AbfBCPVV (ORCPT ); Sun, 3 Feb 2019 10:21:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43584 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726463AbfBCPVV (ORCPT ); Sun, 3 Feb 2019 10:21:21 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0069A31487; Sun, 3 Feb 2019 15:21:21 +0000 (UTC) Received: from krava (ovpn-204-46.brq.redhat.com [10.40.204.46]) by smtp.corp.redhat.com (Postfix) with SMTP id A0FDD5B680; Sun, 3 Feb 2019 15:21:14 +0000 (UTC) Date: Sun, 3 Feb 2019 16:21:13 +0100 From: Jiri Olsa To: Dmitry Vyukov Cc: Ingo Molnar , Peter Zijlstra , LKML , Arnaldo Carvalho de Melo , Alexander Shishkin , Namhyung Kim , luca abeni , Thomas Gleixner , Oleg Nesterov , syzkaller Subject: Re: perf_event_open+clone = unkillable process Message-ID: <20190203152113.GA11794@krava> References: <20190202183013.GA10522@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190202183013.GA10522@krava> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Sun, 03 Feb 2019 15:21:21 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 02, 2019 at 07:30:45PM +0100, Jiri Olsa wrote: > On Fri, Feb 01, 2019 at 06:06:03PM +0100, Dmitry Vyukov wrote: > > On Fri, Feb 1, 2019 at 5:48 PM Dmitry Vyukov wrote: > > > > > > Hello, > > > > > > The following program creates an unkillable process that eats CPU. > > > /proc/pid/stack is empty, I am not sure what other info I can provide. > > > > > > Tested is on upstream commit 4aa9fc2a435abe95a1e8d7f8c7b3d6356514b37a. > > > Config is attached. > > > > Looking through other reproducers that create unkillable processes, I > > think I found a much simpler reproducer (below). It's single threaded > > and just setups SIGBUS handler and does timer_create+timer_settime to > > send repeated SIGBUS. The resulting process can't be killed with > > SIGKILL. > > +Thomas for timers. > > nice, I managed to kill it by strace ;-) > > [jolsa@krava perf]$ strace -p 10725 > strace: Process 10725 attached > --- stopped by SIGBUS --- > --- stopped by SIGBUS --- > --- stopped by SIGBUS --- > --- stopped by SIGBUS --- > +++ killed by SIGINT +++ fyi I can no longer reproduce the kill via strace.. not sure what was different jirka