From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757068AbdKGWoU (ORCPT ); Tue, 7 Nov 2017 17:44:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:38172 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754275AbdKGWoT (ORCPT ); Tue, 7 Nov 2017 17:44:19 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D2B04217C0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Tue, 7 Nov 2017 17:44:13 -0500 From: Steven Rostedt To: Linus Torvalds Cc: Kees Cook , "Tobin C. Harding" , "Paul E. McKenney" , Andy Lutomirski , Joe Perches , Network Development , David Miller , "kernel-hardening@lists.openwall.com" , "Jason A. Donenfeld" , "Theodore Ts'o" , Paolo Bonzini , Tycho Andersen , "Roberts, William C" , Tejun Heo , Jordan Glover , Greg KH , Petr Mladek , Ian Campbell , Sergey Senozhatsky , Catalin Marinas , Will Deacon , Chris Fries , Dave Weinstein , Daniel Micay , Djalal Harouni , Linux Kernel Mailing List , Peter Zijlstra Subject: Re: [PATCH v3] scripts: add leaking_addresses.pl Message-ID: <20171107174413.00e51a3f@gandalf.local.home> In-Reply-To: References: <1509945567-11801-1-git-send-email-me@tobin.cc> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 7 Nov 2017 13:44:01 -0800 Linus Torvalds wrote: > > Looking other places that stand out, it seems like > > /proc/lockdep_chains and /proc/lockdep (CONFIG_LOCKDEP=y) has a ton of > > %p usage. It's unclear to me if a hash is sufficient for meaningful > > debugging there? > > Maybe not, but that is also _so_ esoteric that I suspect the right fix > is to just make it root-only readable. Also note, I don't believe anyone should be running a LOCKDEP configured kernel in a production (secured) environment. As it adds quite a bit of overhead. It's something you run on test environments to make sure it doesn't detect any possible deadlocks. > > I've never used it, we should check with people who have. I get the > feeling that this is purely for PeterZ debugging. I've used it. But then again, I also debug lockdep ;-) > > The very first commit that introduced that code actually has a > > (FIXME: should go into debugfs) > > so I suspect it never should have been user-readable to begin with. I > guess it makes some things easier, but it really is *very* different > from things like profiling. Want me to whip up a patch to move the file? -- Steve > > Profiling you often *cannot* do as root - some things you profile > really shouldn't be run as root, and might even refuse to do so. So > requiring you to be root just to get a kernel profile is very bad. > > But looking at lockdep stats? Yeah, 'sudo' isn't so big of a deal. > >