From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751346AbdBXQMX (ORCPT ); Fri, 24 Feb 2017 11:12:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50478 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750995AbdBXQMQ (ORCPT ); Fri, 24 Feb 2017 11:12:16 -0500 Date: Fri, 24 Feb 2017 17:03:54 +0100 From: Oleg Nesterov To: Andrew Morton , "Eric W. Biederman" Cc: Aleksa Sarai , Andy Lutomirski , Attila Fazekas , Jann Horn , Kees Cook , Michal Hocko , Ulrich Obergfell , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/2] fix the traced mt-exec deadlock Message-ID: <20170224160354.GA845@redhat.com> References: <20170213141452.GA30203@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170213141452.GA30203@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Fri, 24 Feb 2017 16:03:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Eric, our discussion was a bit confusing, and it seems that we did not fully convince each other. So let me ask what do you finally think about this fix. Let me repeat. Even if I do not agree with some of your objections, I do agree that 1/2 does not look nice and clean. And we seem to agree that either way, with or without this fix, we need more changes in this area. But we need a simple and backportable fix for stable trees, say for rhel7. This bug was reported many times, and this is the simplest solution I was able to find. Oleg. On 02/13, Oleg Nesterov wrote: > > Hello, > > Lets finally fix this problem, it was reported several times. I still think that > in the longer term we should (try to) rework the security hooks and (partially) > revert this change, but this is not trivial and we need something backportable > anyway. > > Eric, Jann, we already discussed this change. 1/2 is the same patch I suggested 3 > months ago except now it compiles and moves flush_signal_handlers() to de_thread(). > > Both patches ask for subsequent cleanups, see the changelogs. > > Oleg. > > arch/x86/ia32/ia32_aout.c | 3 ++ > fs/binfmt_aout.c | 3 ++ > fs/binfmt_elf.c | 6 ++- > fs/binfmt_elf_fdpic.c | 4 ++ > fs/binfmt_flat.c | 3 ++ > fs/exec.c | 128 +++++++++++++++++++++++----------------------- > include/linux/binfmts.h | 1 + > kernel/exit.c | 5 +- > kernel/signal.c | 21 +++++--- > 9 files changed, 101 insertions(+), 73 deletions(-)