Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754858AbXISTaj (ORCPT ); Wed, 19 Sep 2007 15:30:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754305AbXISTaP (ORCPT ); Wed, 19 Sep 2007 15:30:15 -0400 Received: from extu-mxob-2.symantec.com ([216.10.194.135]:32457 "EHLO extu-mxob-2.symantec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753924AbXISTaO (ORCPT ); Wed, 19 Sep 2007 15:30:14 -0400 Date: Wed, 19 Sep 2007 20:29:07 +0100 (BST) From: Hugh Dickins X-X-Sender: hugh@blonde.wat.veritas.com To: Mikael Pettersson cc: "H. Peter Anvin" , james-p@moving-picture.com, linux-kernel@vger.kernel.org, aarapov@redhat.com, akpm@linux-foundation.org Subject: Re: [PATCH -mm] Don't truncate /proc/PID/environ at 4096 characters In-Reply-To: <18161.27621.630048.643513@alkaid.it.uu.se> Message-ID: References: <200709191454.l8JEsAQO010080@harpo.it.uu.se> <46F1475B.5050107@zytor.com> <18161.27621.630048.643513@alkaid.it.uu.se> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 798 Lines: 20 On Wed, 19 Sep 2007, Mikael Pettersson wrote: > H. Peter Anvin writes: > > Mikael Pettersson wrote: > > > Does /proc/PID/mem even work? If I do `strace cat /proc/PID/mem > /dev/null' > > > for a known good PID, the first read() from /proc/PID/mem fails with ESRCH, > > > > Of course it does. Address zero isn't typically mapped. > > Indeed. My bad :-( No, not quite. Peter explains why "cat /proc/self/mem" gets EIO, but you were seeing "cat /proc/other/mem" get ESRCH: that's from the stringent !MAY_PTRACE || !ptrace_may_attach checks. Hugh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/