The following commit has been merged into the core/rcu branch of tip: Commit-ID: 03bd2983d7a9f898fd89f8f7215c3e56732d8ecd Gitweb: https://git.kernel.org/tip/03bd2983d7a9f898fd89f8f7215c3e56732d8ecd Author: Paul E. McKenney <paulmck@xxxxxxxxxx> AuthorDate: Thu, 10 Oct 2019 09:05:27 -07:00 Committer: Paul E. McKenney <paulmck@xxxxxxxxxx> CommitterDate: Mon, 09 Dec 2019 12:37:50 -08:00 rcu: Use lockdep rather than comment to enforce lock held The rcu_preempt_check_blocked_tasks() function has a comment that states that the rcu_node structure's ->lock must be held, which might be informative, but which carries little weight if not read. This commit therefore removes this comment in favor of raw_lockdep_assert_held_rcu_node(), which will complain quite visibly if the required lock is not held. Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- kernel/rcu/tree_plugin.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index fe5f448..ed54d36 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -648,8 +648,7 @@ static void rcu_read_unlock_special(struct task_struct *t) * Check that the list of blocked tasks for the newly completed grace * period is in fact empty. It is a serious bug to complete a grace * period that still has RCU readers blocked! This function must be - * invoked -before- updating this rnp's ->gp_seq, and the rnp's ->lock - * must be held by the caller. + * invoked -before- updating this rnp's ->gp_seq. * * Also, if there are blocked tasks on the list, they automatically * block the newly created grace period, so set up ->gp_tasks accordingly. @@ -659,6 +658,7 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) struct task_struct *t; RCU_LOCKDEP_WARN(preemptible(), "rcu_preempt_check_blocked_tasks() invoked with preemption enabled!!!\n"); + raw_lockdep_assert_held_rcu_node(rnp); if (WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp))) dump_blkd_tasks(rnp, 10); if (rcu_preempt_has_tasks(rnp) &&
|