From patchwork Tue Dec 1 08:52:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 336787 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 CB180C83011 for ; Tue, 1 Dec 2020 09:19:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87EF0206CA for ; Tue, 1 Dec 2020 09:19:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RTpwM+XL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390588AbgLAJTG (ORCPT ); Tue, 1 Dec 2020 04:19:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:47504 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389663AbgLAJKS (ORCPT ); Tue, 1 Dec 2020 04:10:18 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8D44920656; Tue, 1 Dec 2020 09:10:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1606813803; bh=KS5sNnxLHtIs9E9OLCHNsPezCmnd4ggTIjINV5NcBbE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RTpwM+XLx4C/M4IdEFK3gB4kQWY1TMWL4K3n19wApmu6GO7HPbo+7F5RnCjonFCch mC5TAGrZuGElK4TSKaOlpIbR6XUdqpGI32y87meMpJwU/QW9XZ5ltOZZH1z9AdFol3 DxvEx9GjXH9SYnJw+JyyH5/GXh8KqVqtBKoq2rFM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Boqun Feng , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 5.9 064/152] lockdep: Put graph lock/unlock under lock_recursion protection Date: Tue, 1 Dec 2020 09:52:59 +0100 Message-Id: <20201201084720.323912400@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201201084711.707195422@linuxfoundation.org> References: <20201201084711.707195422@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Boqun Feng [ Upstream commit 43be4388e94b915799a24f0eaf664bf95b85231f ] A warning was hit when running xfstests/generic/068 in a Hyper-V guest: [...] ------------[ cut here ]------------ [...] DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled()) [...] WARNING: CPU: 2 PID: 1350 at kernel/locking/lockdep.c:5280 check_flags.part.0+0x165/0x170 [...] ... [...] Workqueue: events pwq_unbound_release_workfn [...] RIP: 0010:check_flags.part.0+0x165/0x170 [...] ... [...] Call Trace: [...] lock_is_held_type+0x72/0x150 [...] ? lock_acquire+0x16e/0x4a0 [...] rcu_read_lock_sched_held+0x3f/0x80 [...] __send_ipi_one+0x14d/0x1b0 [...] hv_send_ipi+0x12/0x30 [...] __pv_queued_spin_unlock_slowpath+0xd1/0x110 [...] __raw_callee_save___pv_queued_spin_unlock_slowpath+0x11/0x20 [...] .slowpath+0x9/0xe [...] lockdep_unregister_key+0x128/0x180 [...] pwq_unbound_release_workfn+0xbb/0xf0 [...] process_one_work+0x227/0x5c0 [...] worker_thread+0x55/0x3c0 [...] ? process_one_work+0x5c0/0x5c0 [...] kthread+0x153/0x170 [...] ? __kthread_bind_mask+0x60/0x60 [...] ret_from_fork+0x1f/0x30 The cause of the problem is we have call chain lockdep_unregister_key() -> lockdep_unlock() -> arch_spin_unlock() -> __pv_queued_spin_unlock_slowpath() -> pv_kick() -> __send_ipi_one() -> trace_hyperv_send_ipi_one(). Although this particular warning is triggered because Hyper-V has a trace point in ipi sending, but in general arch_spin_unlock() may call another function having a trace point in it, so put the arch_spin_lock() and arch_spin_unlock() after lock_recursion protection to fix this problem and avoid similiar problems. Signed-off-by: Boqun Feng Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20201113110512.1056501-1-boqun.feng@gmail.com Signed-off-by: Sasha Levin --- kernel/locking/lockdep.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 3eb35ad1b5241..04134a242f3d5 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -108,19 +108,21 @@ static inline void lockdep_lock(void) { DEBUG_LOCKS_WARN_ON(!irqs_disabled()); + __this_cpu_inc(lockdep_recursion); arch_spin_lock(&__lock); __owner = current; - __this_cpu_inc(lockdep_recursion); } static inline void lockdep_unlock(void) { + DEBUG_LOCKS_WARN_ON(!irqs_disabled()); + if (debug_locks && DEBUG_LOCKS_WARN_ON(__owner != current)) return; - __this_cpu_dec(lockdep_recursion); __owner = NULL; arch_spin_unlock(&__lock); + __this_cpu_dec(lockdep_recursion); } static inline bool lockdep_assert_locked(void)