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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 4F1E7C2D0CD for ; Tue, 17 Dec 2019 15:25:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2FEF32072D for ; Tue, 17 Dec 2019 15:25:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727897AbfLQPZP (ORCPT ); Tue, 17 Dec 2019 10:25:15 -0500 Received: from mx2.suse.de ([195.135.220.15]:42974 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727723AbfLQPZP (ORCPT ); Tue, 17 Dec 2019 10:25:15 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 42562AC5F; Tue, 17 Dec 2019 15:25:13 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 6F254DA81D; Tue, 17 Dec 2019 16:25:11 +0100 (CET) Date: Tue, 17 Dec 2019 16:25:11 +0100 From: David Sterba To: Randy Dunlap Cc: Josh Poimboeuf , Stephen Rothwell , Linux Next Mailing List , Linux Kernel Mailing List , Linux Btrfs , Peter Zijlstra Subject: Re: linux-next: Tree for Dec 6 (objtool, lots in btrfs) Message-ID: <20191217152511.GG3929@suse.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Randy Dunlap , Josh Poimboeuf , Stephen Rothwell , Linux Next Mailing List , Linux Kernel Mailing List , Linux Btrfs , Peter Zijlstra References: <20191211134929.GL3929@twin.jikos.cz> <20191212184725.db3ost7rcopotr5u@treble> <20191213235054.6k2lcnwa63r26zwi@treble> <20191214054515.ougsr5ykhl3vvy57@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-next-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-next@vger.kernel.org On Fri, Dec 13, 2019 at 11:05:18PM -0800, Randy Dunlap wrote: > OK, that fixes most of them, but still leaves these 2: > > btrfs006.out:fs/btrfs/extent_io.o: warning: objtool: __set_extent_bit()+0x536: unreachable instruction Hard to read from the assembly what C statement is it referring to. I think there are also several functions inlined, I don't see anything suspicious inside __set_extent_bit itself. > btrfs006.out:fs/btrfs/relocation.o: warning: objtool: add_tree_block()+0x501: unreachable instruction Probably also heavily inlined, the function has like 50 lines, a few non-trivial function calls but the offset in the warning suggests a larger size. While browsing the callees I noticed that both have in common a function that is supposed to print and stop at fatal errors. They're extent_io_tree_panic (extent_io.c) and backref_tree_panic (relocation.c). Both call btrfs_panic which is a macro: 3239 #define btrfs_panic(fs_info, errno, fmt, args...) \ 3240 do { \ 3241 __btrfs_panic(fs_info, __func__, __LINE__, errno, fmt, ##args); \ 3242 BUG(); \ 3243 } while (0) There are no conditionals and BUG has the __noreturn annotation (unreachable()) so all is in place and I don't have better ideas what's causing the reports.