From 090c1685fd628a8c191d77b5267a7dc226246a5b Mon Sep 17 00:00:00 2001 From: "Joel Fernandes (Google)" Date: Fri, 5 Oct 2018 16:18:11 -0700 Subject: [PATCH] doc: rcu: Add more rationale for using rcu_read_lock_sched in checklist This commit explains why rcu_read_lock_sched is better than using preempt_disable. Signed-off-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney --- Documentation/RCU/checklist.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt index 49747717d905..8860ab2a897a 100644 --- a/Documentation/RCU/checklist.txt +++ b/Documentation/RCU/checklist.txt @@ -63,7 +63,7 @@ over a rather long period of time, but improvements are always welcome! pointer must be covered by rcu_read_lock(), rcu_read_lock_bh(), rcu_read_lock_sched(), or by the appropriate update-side lock. Disabling of preemption can serve as rcu_read_lock_sched(), but - is less readable. + is less readable and prevents lockdep from detecting locking issues. Letting RCU-protected pointers "leak" out of an RCU read-side critical section is every bid as bad as letting them leak out