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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 3B38DC282DD for ; Fri, 10 Jan 2020 19:46:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 17DB9205F4 for ; Fri, 10 Jan 2020 19:46:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728556AbgAJTqi (ORCPT ); Fri, 10 Jan 2020 14:46:38 -0500 Received: from mx2.suse.de ([195.135.220.15]:49252 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727812AbgAJTqi (ORCPT ); Fri, 10 Jan 2020 14:46:38 -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 E6526AAC2; Fri, 10 Jan 2020 19:46:35 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 10A02DA78B; Fri, 10 Jan 2020 20:46:22 +0100 (CET) Date: Fri, 10 Jan 2020 20:46:22 +0100 From: David Sterba To: dsterba@suse.cz, Josh Poimboeuf , Randy Dunlap , 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: <20200110194622.GS3929@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Josh Poimboeuf , Randy Dunlap , 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> <20191217152954.GH3929@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191217152954.GH3929@suse.cz> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Tue, Dec 17, 2019 at 04:29:54PM +0100, David Sterba wrote: > Separating the definitions by #ifdef looks ok, I'd rather do separate > definitions of ASSERT too, to avoid the ternary operator. I'll send the > patch. Subject: [PATCH] btrfs: separate definition of assertion failure handlers There's a report where objtool detects unreachable instructions, eg.: fs/btrfs/ctree.o: warning: objtool: btrfs_search_slot()+0x2d4: unreachable instruction This seems to be a false positive due to compiler version. The cause is in the ASSERT macro implementation that does the conditional check as IS_DEFINED(CONFIG_BTRFS_ASSERT) and not an #ifdef. To avoid that, use the ifdefs directly. CC: Josh Poimboeuf Reported-by: Randy Dunlap Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 569931dd0ce5..f90b82050d2d 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3157,17 +3157,21 @@ do { \ rcu_read_unlock(); \ } while (0) -__cold -static inline void assfail(const char *expr, const char *file, int line) +#ifdef CONFIG_BTRFS_ASSERT +__cold __noreturn +static inline void assertfail(const char *expr, const char *file, int line) { - if (IS_ENABLED(CONFIG_BTRFS_ASSERT)) { - pr_err("assertion failed: %s, in %s:%d\n", expr, file, line); - BUG(); - } + pr_err("assertion failed: %s, in %s:%d\n", expr, file, line); + BUG(); } -#define ASSERT(expr) \ - (likely(expr) ? (void)0 : assfail(#expr, __FILE__, __LINE__)) +#define ASSERT(expr) \ + (likely(expr) ? (void)0 : assertfail(#expr, __FILE__, __LINE__)) + +#else +static inline void assertfail(const char *expr, const char* file, int line) { } +#define ASSERT(expr) (void)(expr) +#endif /* * Use that for functions that are conditionally exported for sanity tests but --