From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 2/3] tools/objtool: add kasan_check_* to uaccess whitelist Date: Wed, 29 May 2019 11:58:15 +0200 Message-ID: <20190529095815.GL2623@hirez.programming.kicks-ass.net> References: <20190528163258.260144-1-elver@google.com> <20190528163258.260144-2-elver@google.com> <20190528171942.GV2623@hirez.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Marco Elver Cc: Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , the arch/x86 maintainers , Arnd Bergmann , Josh Poimboeuf , "open list:DOCUMENTATION" , LKML , linux-arch , kasan-dev List-Id: linux-arch.vger.kernel.org On Wed, May 29, 2019 at 11:46:10AM +0200, Marco Elver wrote: > On Wed, 29 May 2019 at 10:55, Dmitry Vyukov wrote: > > > > On Tue, May 28, 2019 at 7:19 PM Peter Zijlstra wrote: > > > > > > On Tue, May 28, 2019 at 06:32:57PM +0200, Marco Elver wrote: > > > > This is a pre-requisite for enabling bitops instrumentation. Some bitops > > > > may safely be used with instrumentation in uaccess regions. > > > > > > > > For example, on x86, `test_bit` is used to test a CPU-feature in a > > > > uaccess region: arch/x86/ia32/ia32_signal.c:361 > > > > > > That one can easily be moved out of the uaccess region. Any else? > > > > Marco, try to update config with "make allyesconfig" and then build > > the kernel without this change. > > > > Done. The only instance of the uaccess warning is still in > arch/x86/ia32/ia32_signal.c. > > Change the patch to move this access instead? Let me know what you prefer. Yes, I think that might be best. The whitelist should be minimal. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:57592 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725990AbfE2J61 (ORCPT ); Wed, 29 May 2019 05:58:27 -0400 Date: Wed, 29 May 2019 11:58:15 +0200 From: Peter Zijlstra Subject: Re: [PATCH 2/3] tools/objtool: add kasan_check_* to uaccess whitelist Message-ID: <20190529095815.GL2623@hirez.programming.kicks-ass.net> References: <20190528163258.260144-1-elver@google.com> <20190528163258.260144-2-elver@google.com> <20190528171942.GV2623@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Marco Elver Cc: Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , the arch/x86 maintainers , Arnd Bergmann , Josh Poimboeuf , "open list:DOCUMENTATION" , LKML , linux-arch , kasan-dev Message-ID: <20190529095815.ABT5K8X7jk9WL1CHUG2ggh6dprh0N4QCqlCllFsLtPg@z> On Wed, May 29, 2019 at 11:46:10AM +0200, Marco Elver wrote: > On Wed, 29 May 2019 at 10:55, Dmitry Vyukov wrote: > > > > On Tue, May 28, 2019 at 7:19 PM Peter Zijlstra wrote: > > > > > > On Tue, May 28, 2019 at 06:32:57PM +0200, Marco Elver wrote: > > > > This is a pre-requisite for enabling bitops instrumentation. Some bitops > > > > may safely be used with instrumentation in uaccess regions. > > > > > > > > For example, on x86, `test_bit` is used to test a CPU-feature in a > > > > uaccess region: arch/x86/ia32/ia32_signal.c:361 > > > > > > That one can easily be moved out of the uaccess region. Any else? > > > > Marco, try to update config with "make allyesconfig" and then build > > the kernel without this change. > > > > Done. The only instance of the uaccess warning is still in > arch/x86/ia32/ia32_signal.c. > > Change the patch to move this access instead? Let me know what you prefer. Yes, I think that might be best. The whitelist should be minimal.