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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 C63A7C433DB for ; Mon, 15 Feb 2021 10:45:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8DEE864E52 for ; Mon, 15 Feb 2021 10:45:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230295AbhBOKpZ (ORCPT ); Mon, 15 Feb 2021 05:45:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230042AbhBOKo7 (ORCPT ); Mon, 15 Feb 2021 05:44:59 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89878C061574; Mon, 15 Feb 2021 02:44:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=V15Ko0jDRPYeN/67QW78zQNnD8VcExjAsz8XTcjzpH0=; b=FQLYNszvDOtdGWgZii+WiBb+r2 fQYSdW1pQgcjxIeHKsYCBPXYDfjrGgSYz1rtEucTGaAG6dX+cej25NinPNM71gm5N9Q5aaSGizgA3 tZLza6Lmq3tTUF9yhpPqntfDryVkavGkkudpzJv7eQRJ5GVNkLsP8QNWVA1rgmNXTKHE5+WFlxU2W d4YrJCxMgsSxe/KdxlBHdUrKWhtJ3D9hVvfNIWNvQ753sMvOF3O1oSf1RR6fV5a/dFeENJ7VLQved 4/LCeINLWhTmnHk28Aljj0dDCd8Dn9MbqL8uP+TIJD0H6vKOHRzmDjx0rGOoDfD1SWB1nepAmrd6z HyHahSCg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1lBbMN-0006hm-9U; Mon, 15 Feb 2021 10:44:07 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 7CE01981573; Mon, 15 Feb 2021 11:44:02 +0100 (CET) Date: Mon, 15 Feb 2021 11:44:02 +0100 From: Peter Zijlstra To: Shuah Khan Cc: mingo@redhat.com, will@kernel.org, kvalo@codeaurora.org, davem@davemloft.net, kuba@kernel.org, ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] lockdep: add lockdep_assert_not_held() Message-ID: <20210215104402.GC4507@worktop.programming.kicks-ass.net> References: <37a29c383bff2fb1605241ee6c7c9be3784fb3c6.1613171185.git.skhan@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sun, Feb 14, 2021 at 06:53:01PM +0100, Peter Zijlstra wrote: > On Fri, Feb 12, 2021 at 04:28:42PM -0700, Shuah Khan wrote: > > > +#define lockdep_assert_not_held(l) do { \ > > + WARN_ON(debug_locks && lockdep_is_held(l)); \ > > + } while (0) > > + > > This thing isn't as straight forward as you might think, but it'll > mostly work. > > Notably this thing will misfire when lockdep_off() is employed. It > certainyl needs a comment to explain the subtleties. I think something like so will work, but please double check. diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index b9e9adec73e8..c8b0d292bf8e 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -294,11 +294,15 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) -#define lockdep_assert_held(l) do { \ - WARN_ON(debug_locks && !lockdep_is_held(l)); \ +#define lockdep_assert_held(l) do { \ + WARN_ON(debug_locks && lockdep_is_held(l) == 0)); \ } while (0) -#define lockdep_assert_held_write(l) do { \ +#define lockdep_assert_not_held(l) do { \ + WARN_ON(debug_locks && lockdep_is_held(l) == 1)); \ + } while (0) + +#define lockdep_assert_held_write(l) do { \ WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \ } while (0) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index c1418b47f625..983ba206f7b2 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -5467,7 +5467,7 @@ noinstr int lock_is_held_type(const struct lockdep_map *lock, int read) int ret = 0; if (unlikely(!lockdep_enabled())) - return 1; /* avoid false negative lockdep_assert_held() */ + return -1; /* avoid false negative lockdep_assert_held() */ raw_local_irq_save(flags); check_flags(flags);