From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DCDFAC11F65 for ; Wed, 30 Jun 2021 07:40:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF68361D03 for ; Wed, 30 Jun 2021 07:40:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232990AbhF3Hmk (ORCPT ); Wed, 30 Jun 2021 03:42:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47650 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232573AbhF3Hmj (ORCPT ); Wed, 30 Jun 2021 03:42:39 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07AB0C061766; Wed, 30 Jun 2021 00:40:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=3OELB8OXI9teM7TxgJcDkkpSNV+n0n/1PROLl9QSkrI=; b=JeF/7pQ66uQ5h5XIqWjIXLoQDR WCcF4PLTj0Rx4NSr749dNIpfNiN0RnJOd3kKpdPOTnsN0fcaNS/1eYaWiiH3IT/AthMysoU09fSky a3vQZ5Dq2XsrOdecuVvQT6xKy4A8xqqEvqFuZAdMu7ceREHBtgXQGRdlRjzSE91euE454pVZG+aTD wlAX5WMyxSLn06EBjK130qy567pS3S8rMeaB/6JYnYRF59P61KuWRV7Rynce4UaGXN1VGIGcVhLsO gBjY2LQ5ZpfyGhFzOxqYTGbdlu0TsPqWRT7RiOUgX+4BeGOuabV9GXZ0wbJtyoz0urNhtUcwKo9qB e8hRSzgQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1lyUnn-0053R2-Jq; Wed, 30 Jun 2021 07:38:47 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 78970300204; Wed, 30 Jun 2021 09:38:30 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 6077E201570E3; Wed, 30 Jun 2021 09:38:30 +0200 (CEST) Date: Wed, 30 Jun 2021 09:38:30 +0200 From: Peter Zijlstra To: Matthew Wilcox Cc: Josh Poimboeuf , linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, Ingo Molnar , x86@kernel.org, masahiroy@kernel.org, michal.lkml@markovi.net, Linus Torvalds Subject: Re: [tip: objtool/core] jump_label, x86: Allow short NOPs Message-ID: References: <20210506194158.216763632@infradead.org> <162082558708.29796.10992563428983424866.tip-bot2@tip-bot2> <20210518195004.GD21560@worktop.programming.kicks-ass.net> <20210518202443.GA48949@worktop.programming.kicks-ass.net> <20210519004411.xpx4i6qcnfpyyrbj@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 30, 2021 at 09:07:05AM +0200, Peter Zijlstra wrote: > On Tue, Jun 29, 2021 at 09:35:37PM +0100, Matthew Wilcox wrote: > > On Tue, Jun 29, 2021 at 09:01:25PM +0100, Matthew Wilcox wrote: > > > So this got merged without the corresponding Kbuild update being merged, > > > and my kernel failed to boot. Bisect got as far as > > > > > > $ git bisect good > > > Bisecting: 4 revisions left to test after this (roughly 2 steps) > > > [ab3257042c26d0cd44793c741e2f89bf38b21fe8] jump_label, x86: Allow short NOPs > > > > > > before my sluggish memory remembered this thread from six weeks ago. > > > > > > So if anybody else hits this, do a make clean. > > > > Actually, this is a different bug with the same symptom. > > > > Applying the patch from Peter, and running it: > > > > $ ./.build_test_kernel-x86_64/tools/objtool/objtool check -abdJsuld .build_test_kernel-x86_64/vmlinux.o > > nr_sections: 15446 > > section_bits: 13 > > nr_symbols: 116448 > > symbol_bits: 16 > > max_reloc: 8031700 > > tot_reloc: 12477754 > > reloc_bits: 19 > > nr_insns: 2523443 > > .build_test_kernel-x86_64/vmlinux.o: warning: objtool: want_init_on_free()+0x0: jump-label unpatched > > > > This is against a freshly built kernel -- i removed the build directory, > > copied in a .config file and built a fresh kernel. > > You happen to have said .config for me? Also GCC version I suppose. The thing I'm wondering about in particular is what translation unit is responsible for that symbol. AFAICT the function itself is an inline from linux/mm.h, but I cannot find any of the files or functions it's used in as being excluded from objtool coverage :/