From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964989Ab3GLNcu (ORCPT ); Fri, 12 Jul 2013 09:32:50 -0400 Received: from terminus.zytor.com ([198.137.202.10]:59771 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964807Ab3GLNcs (ORCPT ); Fri, 12 Jul 2013 09:32:48 -0400 Date: Fri, 12 Jul 2013 06:29:29 -0700 From: tip-bot for Michel Lespinasse Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, rusty@rustcorp.com.au, peterz@infradead.org, srivatsa.bhat@linux.vnet.ibm.com, akpm@linux-foundation.org, rostedt@goodmis.org, paulmck@us.ibm.com, ak@linux.intel.com, tglx@linutronix.de, oleg@redhat.com, walken@google.com, laijs@cn.fujitsu.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, rusty@rustcorp.com.au, peterz@infradead.org, srivatsa.bhat@linux.vnet.ibm.com, paulmck@us.ibm.com, akpm@linux-foundation.org, rostedt@goodmis.org, ak@linux.intel.com, oleg@redhat.com, tglx@linutronix.de, laijs@cn.fujitsu.com, walken@google.com In-Reply-To: <20130708212352.1769031C15E@corp2gmr1-1.hot.corp.google.com> References: <20130708212352.1769031C15E@corp2gmr1-1.hot.corp.google.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:core/locking] lglock: Update lockdep annotations to report recursive local locks Git-Commit-ID: c4be9cb4f19cbd534a6c4c334cd48d8bb483e17a X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (terminus.zytor.com [127.0.0.1]); Fri, 12 Jul 2013 06:29:35 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: c4be9cb4f19cbd534a6c4c334cd48d8bb483e17a Gitweb: http://git.kernel.org/tip/c4be9cb4f19cbd534a6c4c334cd48d8bb483e17a Author: Michel Lespinasse AuthorDate: Mon, 8 Jul 2013 14:23:51 -0700 Committer: Ingo Molnar CommitDate: Fri, 12 Jul 2013 13:51:19 +0200 lglock: Update lockdep annotations to report recursive local locks Oleg Nesterov recently noticed that the lockdep annotations in lglock.c are not sufficient to detect some obvious deadlocks, such as lg_local_lock(LOCK) + lg_local_lock(LOCK) or spin_lock(X) + lg_local_lock(Y) vs lg_local_lock(Y) + spin_lock(X). Both issues are easily fixed by indicating to lockdep that lglock's local locks are not recursive. We shouldn't use the rwlock acquire/release functions here, as lglock doesn't share the same semantics. Instead we can base our lockdep annotations on the lock_acquire_shared (for local lglock) and lock_acquire_exclusive (for global lglock) helpers. I am not proposing new lglock specific helpers as I don't see the point of the existing second level of helpers :) Noticed-by: Oleg Nesterov Signed-off-by: Michel Lespinasse Cc: Lai Jiangshan Cc: "Srivatsa S. Bhat" Cc: Rusty Russell Cc: Andi Kleen Cc: "Paul E. McKenney" Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20130708212352.1769031C15E@corp2gmr1-1.hot.corp.google.com Signed-off-by: Ingo Molnar --- kernel/lglock.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/lglock.c b/kernel/lglock.c index 6535a66..86ae2ae 100644 --- a/kernel/lglock.c +++ b/kernel/lglock.c @@ -21,7 +21,7 @@ void lg_local_lock(struct lglock *lg) arch_spinlock_t *lock; preempt_disable(); - rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_); + lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_); lock = this_cpu_ptr(lg->lock); arch_spin_lock(lock); } @@ -31,7 +31,7 @@ void lg_local_unlock(struct lglock *lg) { arch_spinlock_t *lock; - rwlock_release(&lg->lock_dep_map, 1, _RET_IP_); + lock_release(&lg->lock_dep_map, 1, _RET_IP_); lock = this_cpu_ptr(lg->lock); arch_spin_unlock(lock); preempt_enable(); @@ -43,7 +43,7 @@ void lg_local_lock_cpu(struct lglock *lg, int cpu) arch_spinlock_t *lock; preempt_disable(); - rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_); + lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_); lock = per_cpu_ptr(lg->lock, cpu); arch_spin_lock(lock); } @@ -53,7 +53,7 @@ void lg_local_unlock_cpu(struct lglock *lg, int cpu) { arch_spinlock_t *lock; - rwlock_release(&lg->lock_dep_map, 1, _RET_IP_); + lock_release(&lg->lock_dep_map, 1, _RET_IP_); lock = per_cpu_ptr(lg->lock, cpu); arch_spin_unlock(lock); preempt_enable(); @@ -65,7 +65,7 @@ void lg_global_lock(struct lglock *lg) int i; preempt_disable(); - rwlock_acquire(&lg->lock_dep_map, 0, 0, _RET_IP_); + lock_acquire_exclusive(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_); for_each_possible_cpu(i) { arch_spinlock_t *lock; lock = per_cpu_ptr(lg->lock, i); @@ -78,7 +78,7 @@ void lg_global_unlock(struct lglock *lg) { int i; - rwlock_release(&lg->lock_dep_map, 1, _RET_IP_); + lock_release(&lg->lock_dep_map, 1, _RET_IP_); for_each_possible_cpu(i) { arch_spinlock_t *lock; lock = per_cpu_ptr(lg->lock, i);