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=-6.8 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 2C9D8C433E0 for ; Mon, 10 Aug 2020 12:26:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0475D20734 for ; Mon, 10 Aug 2020 12:26:52 +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="LEZPgwYs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726621AbgHJM0u (ORCPT ); Mon, 10 Aug 2020 08:26:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726450AbgHJM0u (ORCPT ); Mon, 10 Aug 2020 08:26:50 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15967C061756 for ; Mon, 10 Aug 2020 05:26:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=1gdxTGCOCXOCiVyxqJ17K13XKmESbQXv1vfC8SpqAJA=; b=LEZPgwYsopDWi/TFlGBelqitz8 GWM1tUOy9JbxW+XALwE0rW6SzWLQ75FJEvx8JZ7lvXF2P/sVYinQWKdZ2o2I+nvPfGvTWmt4Trz4y a9AbkplhpmUujVaPN0iAwgQJy11lFZRp6uoxKAZ8B9FCCcrpHi0RMIjJX2Z2z1l2Hk0CsnUBFBi+1 lTe4CEbzC9M4dAGKrcoh6BtezPuTUB+zxa/YGwb8W12/sCDIhQ51WD+cMwKHEK99Xz5hAjMHyLVRs NMrfZDLBnLenE7T0TQfz+fuVrbjRjTpzq+94ApbeVZrrRNnljLmFhZ88XoJcshQRV3N1cgP1KBaON XH5c+/tQ==; 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 1k56t0-0005we-Se; Mon, 10 Aug 2020 12:26:43 +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 9C7713003E5; Mon, 10 Aug 2020 14:26:41 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5D5D722281168; Mon, 10 Aug 2020 14:26:41 +0200 (CEST) Date: Mon, 10 Aug 2020 14:26:41 +0200 From: peterz@infradead.org To: tglx@linutronix.de, mingo@kernel.org, will@kernel.org Cc: x86@kernel.org, linux-kernel@vger.kernel.org, elver@google.com, paulmck@kernel.org, rostedt@goodmis.org, rjw@rjwysocki.net Subject: [RFC][PATCH v1.1 3/3] lockdep,trace: Expose tracepoints Message-ID: <20200810122641.GW2674@hirez.programming.kicks-ass.net> References: <20200807192336.405068898@infradead.org> <20200807193018.160331394@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200807193018.160331394@infradead.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Subject: lockdep,trace: Expose tracepoints From: Peter Zijlstra Date: Fri Aug 7 20:53:16 CEST 2020 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 @@ -4977,6 +4977,8 @@ 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) { @@ -5001,7 +5003,6 @@ 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(); @@ -5013,13 +5014,15 @@ 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(); @@ -5205,8 +5208,6 @@ __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) @@ -5225,6 +5226,8 @@ void lock_contended(struct lockdep_map * { unsigned long flags; + trace_lock_contended(lock, ip); + if (unlikely(!lock_stat || !debug_locks)) return; @@ -5234,7 +5237,6 @@ 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); @@ -5245,6 +5247,8 @@ void lock_acquired(struct lockdep_map *l { unsigned long flags; + trace_lock_acquired(lock, ip); + if (unlikely(!lock_stat || !debug_locks)) return;