From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3467 invoked by alias); 30 Oct 2014 13:12:04 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 3416 invoked by uid 89); 30 Oct 2014 13:12:03 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Thu, 30 Oct 2014 13:12:02 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s9UDBwWK002555 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 30 Oct 2014 09:11:59 -0400 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s9UDBuPb027415; Thu, 30 Oct 2014 09:11:57 -0400 Message-ID: <5452391C.8020709@redhat.com> Date: Thu, 30 Oct 2014 13:12:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: Daniel Colascione , gdb-patches@sourceware.org Subject: Re: [PATCH] Warn users about mismatched PID namespaces References: <5451AB7E.40709@dancol.org> <54522DC7.2090100@redhat.com> <54522FE0.9050508@dancol.org> <545233C8.4070402@redhat.com> <5452345D.4040601@dancol.org> In-Reply-To: <5452345D.4040601@dancol.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-10/txt/msg00847.txt.bz2 On 10/30/2014 12:51 PM, Daniel Colascione wrote: > On 10/30/2014 12:49 PM, Pedro Alves wrote: >> On 10/30/2014 12:32 PM, Daniel Colascione wrote: >>> On 10/30/2014 12:23 PM, Pedro Alves wrote: >>>> On 10/30/2014 03:07 AM, Daniel Colascione wrote: >>>> >>>>> diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c >>>>> index 352fac1..4089417 100644 >>>>> - --- a/gdb/linux-thread-db.c >>>>> +++ b/gdb/linux-thread-db.c >>>>> @@ -1223,6 +1223,25 @@ thread_db_new_objfile (struct objfile *objfile) >>>>> static void >>>>> thread_db_inferior_created (struct target_ops *target, int from_tty) >>>>> { >>>>> + /* If the child is in a different PID namespace, its idea of its PID >>>>> + will differ from our idea of its PID. When we scan the child's >>>>> + thread list, we'll mistakenly think it has no threads since the >>>>> + thread PID fields won't match the PID we give to >>>>> + libthread_db. */ >>>> >>>> Why not give libthread_db the right PID then? >>> >>> How do you suggest find it? >> >> Isn't it visible somewhere in /proc ? > > Not AFAICT, but maybe I overlooked something. Oh well... Fine with me to add a warning then. I'd appreciate that the comment in the code mentioned that that's no way to retrieve the right PID. I see a couple minor formatting issues in the patch, but nothing major. Do you have your copyright assignment for GDB on file? Seems you're only covered for emacs atm, unfortunately. > >> >>> There's some talk on LKML of adding the necessary system call, but it's not in-tree yet. >> >> Do you have a url handy? > > https://lwn.net/Articles/602987/ Thanks. Thanks, Pedro Alves