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=-6.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 DF488C433E1 for ; Thu, 20 Aug 2020 07:50:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADE032076E for ; Thu, 20 Aug 2020 07:50:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="XQ8E8gXo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725910AbgHTHue (ORCPT ); Thu, 20 Aug 2020 03:50:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726851AbgHTHuM (ORCPT ); Thu, 20 Aug 2020 03:50:12 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 86924C061383 for ; Thu, 20 Aug 2020 00:50:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=FVA3agAYNH03NGG2EyaMJvjyPHeKiT2gHRMfl74rZEg=; b=XQ8E8gXowzXI4xMrerFcNycRrL Z8AqszcKj5PV+4Eod+GJ6uIRRZlg1+HB/wB+odgZ/f6KV5ztaYJR+Y6sP9oX2Hzt8WNS/GVVjypU3 gQeJGQPtI/p2zGH7stR8P0Vx6QuZ8e63mcKLD5U5cPkzTK+o2xGub1zyiN3X7gZRrck3d7lqTDUkV rON76Z9Zg7yRLLilkNQBZGvsZ2bhS/e/ChTbJcxM0kvWVkvHvPG7Uh8S6Xp/yGsr5mXySJ4FgQXyC 1tgR09P1apsSwGnK5FStc+s9vH712yOSfaYmUEExxDvKI2rkurpHW+iF5x92ZXawXz3zppw2z+UfT +j2+resQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8fKX-0000Mm-77; Thu, 20 Aug 2020 07:49:49 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id EDA25306E56; Thu, 20 Aug 2020 09:49:43 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 7327728B7E847; Thu, 20 Aug 2020 09:49:43 +0200 (CEST) Message-ID: <20200820074640.810404638@infradead.org> User-Agent: quilt/0.66 Date: Thu, 20 Aug 2020 09:30:40 +0200 From: Peter Zijlstra To: linux-kernel@vger.kernel.org, mingo@kernel.org, will@kernel.org Cc: npiggin@gmail.com, elver@google.com, jgross@suse.com, paulmck@kernel.org, rostedt@goodmis.org, rjw@rjwysocki.net, joel@joelfernandes.org, svens@linux.ibm.com, tglx@linutronix.de, peterz@infradead.org Subject: [PATCH 9/9] lockdep,trace: Expose tracepoints References: <20200820073031.886217423@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The lockdep tracepoints are under the lockdep recursion counter, this has a bunch of nasty side effects: - TRACE_IRQFLAGS doesn't work across the entire tracepoint - RCU-lockdep doesn't see the tracepoints either, hiding numerous "suspicious RCU usage" warnings. Pull the trace_lock_*() tracepoints completely out from under the lockdep recursion handling and completely rely on the trace level recusion handling -- also, tracing *SHOULD* not be taking locks in any case. Signed-off-by: Peter Zijlstra (Intel) --- kernel/locking/lockdep.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -5044,6 +5044,8 @@ void lock_acquire(struct lockdep_map *lo { unsigned long flags; + trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); + if (unlikely(current->lockdep_recursion)) { /* XXX allow trylock from NMI ?!? */ if (lockdep_nmi() && !trylock) { @@ -5068,7 +5070,6 @@ void lock_acquire(struct lockdep_map *lo check_flags(flags); current->lockdep_recursion++; - trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); __lock_acquire(lock, subclass, trylock, read, check, irqs_disabled_flags(flags), nest_lock, ip, 0, 0); lockdep_recursion_finish(); @@ -5080,13 +5081,15 @@ void lock_release(struct lockdep_map *lo { unsigned long flags; + trace_lock_release(lock, ip); + if (unlikely(current->lockdep_recursion)) return; raw_local_irq_save(flags); check_flags(flags); + current->lockdep_recursion++; - trace_lock_release(lock, ip); if (__lock_release(lock, ip)) check_chain_key(current); lockdep_recursion_finish(); @@ -5272,8 +5275,6 @@ __lock_acquired(struct lockdep_map *lock hlock->holdtime_stamp = now; } - trace_lock_acquired(lock, ip); - stats = get_lock_stats(hlock_class(hlock)); if (waittime) { if (hlock->read) @@ -5292,6 +5293,8 @@ void lock_contended(struct lockdep_map * { unsigned long flags; + trace_lock_contended(lock, ip); + if (unlikely(!lock_stat || !debug_locks)) return; @@ -5301,7 +5304,6 @@ void lock_contended(struct lockdep_map * raw_local_irq_save(flags); check_flags(flags); current->lockdep_recursion++; - trace_lock_contended(lock, ip); __lock_contended(lock, ip); lockdep_recursion_finish(); raw_local_irq_restore(flags); @@ -5312,6 +5314,8 @@ void lock_acquired(struct lockdep_map *l { unsigned long flags; + trace_lock_acquired(lock, ip); + if (unlikely(!lock_stat || !debug_locks)) return;