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=-3.5 required=3.0 tests=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 2CDC1C433DF for ; Wed, 27 May 2020 15:53:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 02381208E4 for ; Wed, 27 May 2020 15:53:50 +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="AtYtwDCs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390469AbgE0Pxt (ORCPT ); Wed, 27 May 2020 11:53:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390394AbgE0PwG (ORCPT ); Wed, 27 May 2020 11:52:06 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A0E0C03E97D for ; Wed, 27 May 2020 08:52:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=odP3stPmOZOoMjCjPPJsvRCJXoVaH54qLCzDu3GZ0VI=; b=AtYtwDCspmyCyvnftoNvgyBBz6 jX3bHZwQQDO2N76RhAv8X6f+8hh7T4uhcYERE885GbwaQwk9owFj5mCQJxvlX5zI+1VEcZ91NRZgR YSAT7+nnyKdSGEBOg19/dD1KAps4QQBtLrYbmsjXl2BEdcJYRK3B1oqVDCyV1OCu4MerSy1PJtgW0 RBVKKEMQ/ICiAnOk1VYfxybBuPcR/fOz6hT3AfUY/EqLuATANuipmF0kRXMhgC1tjf66/B+hd8k1q hvJw81QJLQuE6k8L9WVfiOjIHRnitn5qVTjJSh0p1uTiOPFpcK7+dUyO/r7/stSJHRqHYz0rhq4Rn Ggxv4GlQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdyLQ-0001tv-JO; Wed, 27 May 2020 15:51:52 +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 0E1883079B8; Wed, 27 May 2020 17:51:50 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id C0142201479A7; Wed, 27 May 2020 17:51:49 +0200 (CEST) Message-ID: <20200527155003.407192056@infradead.org> User-Agent: quilt/0.66 Date: Wed, 27 May 2020 17:45:32 +0200 From: Peter Zijlstra To: mingo@kernel.org, will@kernel.org, tglx@linutronix.de Cc: x86@kernel.org, linux-kernel@vger.kernel.org, a.darwish@linutronix.de, rostedt@goodmis.org, bigeasy@linutronix.de, peterz@infradead.org Subject: [PATCH 5/6] lockdep: Prepare for NMI IRQ state tracking References: <20200527154527.233385756@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 There is no reason not to always, accurately, track IRQ state. This change also makes IRQ state tracking ignore lockdep_off(). Signed-off-by: Peter Zijlstra (Intel) --- kernel/locking/lockdep.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3646,7 +3646,12 @@ static void __trace_hardirqs_on_caller(v */ void lockdep_hardirqs_on_prepare(unsigned long ip) { - if (unlikely(!debug_locks || current->lockdep_recursion)) + /* + * Even though NMIs can happen while in lockdep; we only call this + * then the NMI returns to an IRQs enabled context, which guarantees + * we're not in lockdep. + */ + if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion & LOCKDEP_RECURSION_MASK)) return; if (unlikely(lockdep_hardirqs_enabled())) { @@ -3682,9 +3687,11 @@ void lockdep_hardirqs_on_prepare(unsigne current->hardirq_chain_key = current->curr_chain_key; - current->lockdep_recursion++; - __trace_hardirqs_on_caller(); - lockdep_recursion_finish(); + if (!in_nmi()) { + current->lockdep_recursion++; + __trace_hardirqs_on_caller(); + lockdep_recursion_finish(); + } } EXPORT_SYMBOL_GPL(lockdep_hardirqs_on_prepare); @@ -3692,7 +3699,7 @@ void noinstr lockdep_hardirqs_on(unsigne { struct task_struct *curr = current; - if (unlikely(!debug_locks || curr->lockdep_recursion)) + if (DEBUG_LOCKS_WARN_ON(curr->lockdep_recursion & LOCKDEP_RECURSION_MASK)) return; if (lockdep_hardirqs_enabled()) { @@ -3735,8 +3742,10 @@ void noinstr lockdep_hardirqs_off(unsign { struct task_struct *curr = current; - if (unlikely(!debug_locks || curr->lockdep_recursion)) - return; + /* + * Can't test recursion; NMIs can happen while in lockdep. + * Harmless though; all we do is clear hardirqs_enabled. + */ /* * So we're supposed to get called after you mask local IRQs, but for