From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: [PATCH] lockdep: annotate rcu_read_{,un}lock() Date: Thu, 16 Aug 2007 16:25:07 +0200 Message-ID: <1187274307.6114.92.camel@twins> References: <20070815.144628.104052147.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: herbert@gondor.apana.org.au, 123.oleg@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, David Miller , Daniel Walker To: Paul E McKenney , Ingo Molnar Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:52712 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753566AbXHPOZp (ORCPT ); Thu, 16 Aug 2007 10:25:45 -0400 In-Reply-To: <20070815.144628.104052147.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org There seem to be some unbalanced rcu_read_{,un}lock() issues of late, how about doing something like this: Signed-off-by: Peter Zijlstra --- include/linux/lockdep.h | 7 +++++++ include/linux/rcupdate.h | 12 ++++++++++++ kernel/rcupdate.c | 8 ++++++++ 3 files changed, 27 insertions(+) Index: linux-2.6/include/linux/lockdep.h =================================================================== --- linux-2.6.orig/include/linux/lockdep.h +++ linux-2.6/include/linux/lockdep.h @@ -252,6 +252,13 @@ extern void lockdep_init_map(struct lock struct lock_class_key *key, int subclass); /* + * To initialize a lockdep_map statically use this macro. + * Note that _name must not be NULL. + */ +#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ + { .name = (_name), .key = (void *)(_key), } + +/* * Reinitialize a lock key - for cases where there is special locking or * special initialization of locks so that the validator gets the scope * of dependencies wrong: they are either too broad (they need a class-split) Index: linux-2.6/include/linux/rcupdate.h =================================================================== --- linux-2.6.orig/include/linux/rcupdate.h +++ linux-2.6/include/linux/rcupdate.h @@ -41,6 +41,7 @@ #include #include #include +#include /** * struct rcu_head - callback structure for use with RCU @@ -133,6 +134,15 @@ static inline void rcu_bh_qsctr_inc(int extern int rcu_pending(int cpu); extern int rcu_needs_cpu(int cpu); +#ifdef CONFIG_DEBUG_LOCK_ALLOC +extern struct lockdep_map rcu_lock_map; +# define rcu_read_acquire() lock_acquire(&rcu_lock_map, 0, 0, 2, 1, _THIS_IP_) +# define rcu_read_release() lock_release(&rcu_lock_map, 1, _THIS_IP_) +#else +# define rcu_read_acquire() do { } while (0) +# define rcu_read_release() do { } while (0) +#endif + /** * rcu_read_lock - mark the beginning of an RCU read-side critical section. * @@ -166,6 +176,7 @@ extern int rcu_needs_cpu(int cpu); do { \ preempt_disable(); \ __acquire(RCU); \ + rcu_read_acquire(); \ } while(0) /** @@ -175,6 +186,7 @@ extern int rcu_needs_cpu(int cpu); */ #define rcu_read_unlock() \ do { \ + rcu_read_release(); \ __release(RCU); \ preempt_enable(); \ } while(0) Index: linux-2.6/kernel/rcupdate.c =================================================================== --- linux-2.6.orig/kernel/rcupdate.c +++ linux-2.6/kernel/rcupdate.c @@ -49,6 +49,14 @@ #include #include +#ifdef CONFIG_DEBUG_LOCK_ALLOC +static struct lock_class_key rcu_lock_key; +struct lockdep_map rcu_lock_map = + STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key); + +EXPORT_SYMBOL_GPL(rcu_lock_map); +#endif + /* Definition for rcupdate control block. */ static struct rcu_ctrlblk rcu_ctrlblk = { .cur = -300,