From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755875Ab1IGGZT (ORCPT ); Wed, 7 Sep 2011 02:25:19 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:50056 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755744Ab1IGGVC (ORCPT ); Wed, 7 Sep 2011 02:21:02 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 45/55] rcu: check for entering dyntick-idle mode while in read-side critical section Date: Tue, 6 Sep 2011 11:00:39 -0700 Message-Id: <1315332049-2604-45-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.3.2 In-Reply-To: <20110906180015.GA2560@linux.vnet.ibm.com> References: <20110906180015.GA2560@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CONFIG_RCU_FAST_NO_HZ assumes that all calls to rcu_needs_cpu() are outside of all RCU read-side critical sections. This patch adds diagnostic checks to verify this assumption. Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 3 +++ kernel/rcutree.c | 3 +++ 2 files changed, 6 insertions(+), 0 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index e86bc28..8d7efc8 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -233,6 +233,8 @@ static inline void destroy_rcu_head_on_stack(struct rcu_head *head) #ifdef CONFIG_DEBUG_LOCK_ALLOC +#define PROVE_RCU(a) a + extern struct lockdep_map rcu_lock_map; # define rcu_read_acquire() \ lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_) @@ -311,6 +313,7 @@ static inline int rcu_read_lock_sched_held(void) #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ +# define PROVE_RCU(a) do { } while (0) # define rcu_read_acquire() do { } while (0) # define rcu_read_release() do { } while (0) # define rcu_read_acquire_bh() do { } while (0) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 8455043..743a658 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1786,6 +1786,9 @@ static int rcu_pending(int cpu) */ static int rcu_needs_cpu_quick_check(int cpu) { + PROVE_RCU(WARN_ON_ONCE(lock_is_held(&rcu_lock_map))); + PROVE_RCU(WARN_ON_ONCE(lock_is_held(&rcu_bh_lock_map))); + PROVE_RCU(WARN_ON_ONCE(lock_is_held(&rcu_sched_lock_map))); /* RCU callbacks either ready or pending? */ return per_cpu(rcu_sched_data, cpu).nxtlist || per_cpu(rcu_bh_data, cpu).nxtlist || -- 1.7.3.2