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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A686EB64DC for ; Fri, 14 Jul 2023 14:00:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235199AbjGNOA2 (ORCPT ); Fri, 14 Jul 2023 10:00:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234757AbjGNOAZ (ORCPT ); Fri, 14 Jul 2023 10:00:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F20026B5 for ; Fri, 14 Jul 2023 07:00:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 98FDF61D24 for ; Fri, 14 Jul 2023 14:00:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A055DC433C8; Fri, 14 Jul 2023 14:00:21 +0000 (UTC) Date: Fri, 14 Jul 2023 10:00:19 -0400 From: Steven Rostedt To: Cc: regressions@lists.linux.dev, bagasdotme@gmail.com, alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org Subject: Re: radeon.ko/i586: BUG: kernel NULL pointer dereference, address:00000004 Message-ID: <20230714100019.6bf9b1ab@gandalf.local.home> In-Reply-To: <230714143404.M0123570@vega.pgw.jp> References: <55a3bbb1-5b3c-f454-b529-8ee9944cc67c@leemhuis.info> <230714143404.M0123570@vega.pgw.jp> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Jul 2023 14:34:04 +0900 wrote: > >> > So I'm confused about why it's mentioned. Was it backported? > >> > >> Taketo Kabe, could you please help to clean this confusion up? Did you > >> mean 5.19 in https://bugzilla.kernel.org/show_bug.cgi?id=217669#c5 ? And > >> BTW: did you really use a vanilla kernel for your bisection? > > > Reporter Me: > I bisected using freedesktop.org kernel tree, which git commit ID is > in sync with kernel.org > but version number in ./Makefile could be slighty behind. > > Patch in > https://bugzilla.kernel.org/show_bug.cgi?id=217669#c4 > fixed the problem in freedesktop.org kernel 5.18.0-rc2 . > This may explain that in kernel.org tree, the said commit is in kernel-5.19. Even if the bisect did land on this commit, it doesn't make sense. I would think that one of the results of the bisect was incorrect (a pass that should have failed?), as that would lead the bisect down to the wrong conclusion. Now if you you remove this commit and everything works fine, and add it back again and it fails reliably, then I can't argue it is not the commit. But the commit in question kicks off a worker thread at boot up to search for weak functions that were tagged to be traced by the function tracer and sets them to "disabled" to never be traced. Is the function tracer used at all here? I really do not see how this commit affects the code that is crashing. Unless there's something wrong with the way the kworker was set up and it corrupted other kworkers :-/ -- Steve