Documentation/RCU/lockdep.rst

1 .. SPDX-License-Identifier: GPL-2.0
8 aware of when each task enters and leaves any flavor of RCU read-side
18 	rcu_read_lock_bh_held() for RCU-bh.
19 	rcu_read_lock_sched_held() for RCU-sched.
20 	rcu_read_lock_any_held() for any of normal RCU, RCU-bh, and RCU-sched.
33 		Check for RCU read-side critical section.
35 		Check for RCU-bh read-side critical section.
37 		Check for RCU-sched read-side critical section.
39 		Check for SRCU read-side critical section.
43 		invoked by both RCU readers and updaters.
47 		is invoked by both RCU-bh readers and updaters.
51 		is invoked by both RCU-sched readers and updaters.
55 		is invoked by both SRCU readers and updaters.
64 		invoked only by updaters.
75 	file = rcu_dereference_check(fdt->fd[fd],
76 				     lockdep_is_held(&files->file_lock) ||
77 				     atomic_read(&files->count) == 1);
79 This expression picks up the pointer "fdt->fd[fd]" in an RCU-safe manner,
83 1.	An RCU read-side critical section (implicit), or
84 2.	with files->file_lock held, or
87 In case (1), the pointer is picked up in an RCU-safe manner for vanilla
88 RCU read-side critical sections, in case (2) the ->file_lock prevents
94 	file = rcu_dereference_protected(fdt->fd[fd],
95 					 lockdep_is_held(&files->file_lock) ||
96 					 atomic_read(&files->count) == 1);
99 complain even if this was used in an RCU read-side critical section unless
103 to use rcu_dereference_protected() if either the RCU-protected pointer
104 or the RCU-protected data that it points to can change concurrently.
107 traversal primitives check for being called from within an RCU read-side
111 false and they are called from outside any RCU read-side critical section.
114 either within an RCU read-side critical section or with wq->mutex held.
118 		list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node,
119 					lock_is_held(&(wq->mutex).dep_map))