From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mail09.linbit.com (LINBIT Mail Daemon) with ESMTP id 38039106DFEC for ; Mon, 1 Feb 2010 11:40:21 +0100 (CET) Date: Mon, 1 Feb 2010 11:39:33 +0100 From: Oleg Nesterov To: Neil Horman Message-ID: <20100201103933.GA32188@redhat.com> References: <20100121200806.GA29801@shamino.rdu.redhat.com> <20100129151024.GA19249@hmsreliant.think-freely.org> <20100129151458.GC19249@hmsreliant.think-freely.org> <20100131155000.GB13402@redhat.com> <20100131160030.GB1950@localhost.localdomain> <20100201102936.GA31611@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100201102936.GA31611@redhat.com> Cc: jmoskovc@redhat.com, neilb@suse.de, benh@kernel.crashing.org, gregkh@suse.de, takedakn@nttdata.co.jp, linux-kernel@vger.kernel.org, spock@gentoo.org, mingo@redhat.com, viro@zeniv.linux.org.uk, mfasheh@suse.com, akpm@linux-foundation.org, t.sailer@alumni.ethz.ch, shemminger@linux-foundation.org, menage@google.com, abelay@mit.edu, drbd-dev@lists.linbit.com Subject: Re: [Drbd-dev] [PATCH 2/2] exec: allow core_pipe recursion check to look for a value of 1 rather than 0 (v2) List-Id: Coordination of development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 02/01, Oleg Nesterov wrote: > > Oh. And in theory, it is better to change wait_for_helper(). It should > do allow_signal(SIGCHLD) after kernel_thread(). Otherwise, kernel_thread() > can fail if user-space sends SIGCHLD to the forking thread. Well ;) And since allow_signal(SIGCHLD) was called, in theory we should call sys_wait4() + clear_thread_flag(TIF_SIGPENDING) in a loop to protect against the false SIGCHLD. > > > Cough. And why call_usermodehelper_exec() has this strange ->path[0] == '\0' > > > check? > > > > > That I can't explain. I figured I'd let that sleeping dog lie until this got > > striaghtened out and fix it separately if it needed it > > Neil > > Yes, yes, agreed. As I said, this has nothing to do with this series, > even if I am right these (minor) bugs should be fixed separately. Yes. Oleg. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754186Ab0BAKkf (ORCPT ); Mon, 1 Feb 2010 05:40:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46803 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751778Ab0BAKke (ORCPT ); Mon, 1 Feb 2010 05:40:34 -0500 Date: Mon, 1 Feb 2010 11:39:33 +0100 From: Oleg Nesterov To: Neil Horman Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, jmoskovc@redhat.com, mingo@redhat.com, drbd-dev@lists.linbit.com, benh@kernel.crashing.org, t.sailer@alumni.ethz.ch, abelay@mit.edu, gregkh@suse.de, spock@gentoo.org, viro@zeniv.linux.org.uk, neilb@suse.de, mfasheh@suse.com, menage@google.com, shemminger@linux-foundation.org, takedakn@nttdata.co.jp Subject: Re: [PATCH 2/2] exec: allow core_pipe recursion check to look for a value of 1 rather than 0 (v2) Message-ID: <20100201103933.GA32188@redhat.com> References: <20100121200806.GA29801@shamino.rdu.redhat.com> <20100129151024.GA19249@hmsreliant.think-freely.org> <20100129151458.GC19249@hmsreliant.think-freely.org> <20100131155000.GB13402@redhat.com> <20100131160030.GB1950@localhost.localdomain> <20100201102936.GA31611@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100201102936.GA31611@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/01, Oleg Nesterov wrote: > > Oh. And in theory, it is better to change wait_for_helper(). It should > do allow_signal(SIGCHLD) after kernel_thread(). Otherwise, kernel_thread() > can fail if user-space sends SIGCHLD to the forking thread. Well ;) And since allow_signal(SIGCHLD) was called, in theory we should call sys_wait4() + clear_thread_flag(TIF_SIGPENDING) in a loop to protect against the false SIGCHLD. > > > Cough. And why call_usermodehelper_exec() has this strange ->path[0] == '\0' > > > check? > > > > > That I can't explain. I figured I'd let that sleeping dog lie until this got > > striaghtened out and fix it separately if it needed it > > Neil > > Yes, yes, agreed. As I said, this has nothing to do with this series, > even if I am right these (minor) bugs should be fixed separately. Yes. Oleg.