From: Paul E. McKenney Date: Fri, 19 Aug 2011 22:23:19 +0000 (-0700) Subject: rcu: Check for entering dyntick-idle mode while in read-side critical section X-Git-Tag: next-20110914~19^2~10 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=40dea6ea4dfb8eec955cb6a92ce84d0efa60fd27;p=karo-tx-linux.git rcu: Check for entering dyntick-idle mode while in read-side critical section 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 --- diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index e86bc28233ea..8d7efc8a062f 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 8455043c9250..743a658e3df1 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 ||