From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22898 invoked by alias); 7 Nov 2014 12:49:57 -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 22888 invoked by uid 89); 7 Nov 2014 12:49:56 -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,SPF_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; Fri, 07 Nov 2014 12:49:54 +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 sA7Cnnpc018333 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 7 Nov 2014 07:49:49 -0500 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 sA7Cnl64009110; Fri, 7 Nov 2014 07:49:48 -0500 Message-ID: <545CBFEB.7000907@redhat.com> Date: Fri, 07 Nov 2014 12:49:00 -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> In-Reply-To: <5451AB7E.40709@dancol.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-11/txt/msg00133.txt.bz2 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) > { This hook is called even if the current target isn't a native process. E.g., you may have loaded a core, in which case looking at getpid or /proc doesn't make sense. Or you may be debugging with "target sim", or a remote process with gdbserver [1], etc. We need this same check that thread_db_load does: /* Don't attempt to use thread_db for remote targets. */ if (!(target_can_run (¤t_target) || core_bfd)) return 0; [1] BTW, could I interest in giving gdbserver/thread-db.c the same treatment? > + /* 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. */ > + char *our_pid_ns = linux_proc_pid_get_ns (getpid (), "pid"); > + char *inferior_pid_ns = linux_proc_pid_get_ns ( > + ptid_get_pid (inferior_ptid), "pid"); > + > + if (our_pid_ns != NULL && inferior_pid_ns != NULL && Put '&&' at the beginning of the next line. > + strcmp (our_pid_ns, inferior_pid_ns) != 0) > + { > + warning (_ ("Target and debugger are in different PID namespaces; " > + "thread lists and other data are likely unreliable")); > + } > + > + xfree (our_pid_ns); > + xfree (inferior_pid_ns); Please factor this new code to a function; Having it in a function makes it easier to move the caller around if necessary. > + > check_for_thread_db (); > } > > diff --git a/gdb/nat/linux-procfs.c b/gdb/nat/linux-procfs.c > index 30797da..8efccba 100644 > - --- a/gdb/nat/linux-procfs.c > +++ b/gdb/nat/linux-procfs.c > @@ -113,3 +113,22 @@ linux_proc_pid_is_zombie (pid_t pid) > { > return linux_proc_pid_has_state (pid, "Z (zombie)"); > } > + > +/* See linux-procfs.h declaration. */ > + > +char* > +linux_proc_pid_get_ns (pid_t pid, const char *ns) > +{ > + char buf[100]; > + char nsval[64]; > + int ret; > + snprintf (buf, sizeof (buf), "/proc/%d/ns/%s", (int) pid, ns); Use xsnprintf . > > +/* Return an opaque string identifying PID's NS namespace or NULL if > + * the information is unavailable. The returned string must be > + * released with xfree. */ > + > +extern char* linux_proc_pid_get_ns (pid_t pid, const char *ns); Space between char and *. Thanks, Pedro Alves