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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 A5B17C76562 for ; Thu, 27 Feb 2020 14:34:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 79CE424699 for ; Thu, 27 Feb 2020 14:34:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582814062; bh=Zkc7OTubL7ZofJcFmaZdqja1Ms10TSr7KzZjfj/2mig=; h=From:To:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=FmSkX3cajKSsbxKszTR5dNskjtXdmlCy3BKBLqgb8Q+Roexqk7QV/u2LiaTYbQChm cSzO4F+ZoznJt92KNg47M1mzpENHUjjpyPtTuZM/zsicacdGqVRdYigex5zoHwnfdH Dp7AZVIDqMeCCPs3B72vFqPHN8f5f1sHZUSx0k3s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388514AbgB0OeV (ORCPT ); Thu, 27 Feb 2020 09:34:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:45194 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387774AbgB0OeM (ORCPT ); Thu, 27 Feb 2020 09:34:12 -0500 Received: from localhost.localdomain (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AE913246BA; Thu, 27 Feb 2020 14:34:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582814051; bh=Zkc7OTubL7ZofJcFmaZdqja1Ms10TSr7KzZjfj/2mig=; h=From:To:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=ml6+dh+ISU5bWvPtfK+oMIXuMfTuk1i40PQqZt9RySS9tb2PfdKZ4XAOjKRtNZgL0 h2hcbykENjr0rMzvZj+SPOv0xD4cArKAbBl5igvhstB9nUK2cBu/61OTAyXqz6yQYf Ow2adBLv1pXHxv+1az2kAKr/wAePz53mnaAeppuM= From: zanussi@kernel.org To: LKML , linux-rt-users , Steven Rostedt , Thomas Gleixner , Carsten Emde , John Kacur , Sebastian Andrzej Siewior , Daniel Wagner , Tom Zanussi Subject: [PATCH RT 15/23] locking: Make spinlock_t and rwlock_t a RCU section on RT Date: Thu, 27 Feb 2020 08:33:26 -0600 Message-Id: <186fec3947a0cc8b99cbf8211a91c52140813302.1582814004.git.zanussi@kernel.org> X-Mailer: git-send-email 2.14.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior v4.14.170-rt75-rc2 stable review patch. If anyone has any objections, please let me know. ----------- [ Upstream commit 84440022a0e1c8c936d61f8f97593674a295d409 ] On !RT a locked spinlock_t and rwlock_t disables preemption which implies a RCU read section. There is code that relies on that behaviour. Add an explicit RCU read section on RT while a sleeping lock (a lock which would disables preemption on !RT) acquired. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Tom Zanussi --- kernel/locking/rtmutex.c | 6 ++++++ kernel/locking/rwlock-rt.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 4bc01a2a9a88..848d9ed6f053 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1142,6 +1142,7 @@ void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock) void __lockfunc rt_spin_lock(spinlock_t *lock) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); @@ -1157,6 +1158,7 @@ void __lockfunc __rt_spin_lock(struct rt_mutex *lock) void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); @@ -1170,6 +1172,7 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock) spin_release(&lock->dep_map, 1, _RET_IP_); rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock); migrate_enable(); + rcu_read_unlock(); sleeping_lock_dec(); } EXPORT_SYMBOL(rt_spin_unlock); @@ -1201,6 +1204,7 @@ int __lockfunc rt_spin_trylock(spinlock_t *lock) ret = __rt_mutex_trylock(&lock->lock); if (ret) { spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); } else { migrate_enable(); sleeping_lock_dec(); @@ -1217,6 +1221,7 @@ int __lockfunc rt_spin_trylock_bh(spinlock_t *lock) ret = __rt_mutex_trylock(&lock->lock); if (ret) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); } else @@ -1233,6 +1238,7 @@ int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags) ret = __rt_mutex_trylock(&lock->lock); if (ret) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); } diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c index c3b91205161c..0ae8c62ea832 100644 --- a/kernel/locking/rwlock-rt.c +++ b/kernel/locking/rwlock-rt.c @@ -310,6 +310,7 @@ int __lockfunc rt_read_trylock(rwlock_t *rwlock) ret = do_read_rt_trylock(rwlock); if (ret) { rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); } else { migrate_enable(); sleeping_lock_dec(); @@ -327,6 +328,7 @@ int __lockfunc rt_write_trylock(rwlock_t *rwlock) ret = do_write_rt_trylock(rwlock); if (ret) { rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_); + rcu_read_lock(); } else { migrate_enable(); sleeping_lock_dec(); @@ -338,6 +340,7 @@ EXPORT_SYMBOL(rt_write_trylock); void __lockfunc rt_read_lock(rwlock_t *rwlock) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_); do_read_rt_lock(rwlock); @@ -347,6 +350,7 @@ EXPORT_SYMBOL(rt_read_lock); void __lockfunc rt_write_lock(rwlock_t *rwlock) { sleeping_lock_inc(); + rcu_read_lock(); migrate_disable(); rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_); do_write_rt_lock(rwlock); @@ -358,6 +362,7 @@ void __lockfunc rt_read_unlock(rwlock_t *rwlock) rwlock_release(&rwlock->dep_map, 1, _RET_IP_); do_read_rt_unlock(rwlock); migrate_enable(); + rcu_read_unlock(); sleeping_lock_dec(); } EXPORT_SYMBOL(rt_read_unlock); @@ -367,6 +372,7 @@ void __lockfunc rt_write_unlock(rwlock_t *rwlock) rwlock_release(&rwlock->dep_map, 1, _RET_IP_); do_write_rt_unlock(rwlock); migrate_enable(); + rcu_read_unlock(); sleeping_lock_dec(); } EXPORT_SYMBOL(rt_write_unlock); -- 2.14.1