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tracing/osnoise: Use built-in RCU list checking

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list_for_each_entry_rcu() has built-in RCU and lock checking.

Pass cond argument to list_for_each_entry_rcu() to silence false lockdep
warning when CONFIG_PROVE_RCU_LIST is enabled.

Execute as follow:

 [tracing]# echo osnoise > current_tracer
 [tracing]# echo 1 > tracing_on
 [tracing]# echo 0 > tracing_on

The trace_types_lock is held when osnoise_tracer_stop() or
timerlat_tracer_stop() are called in the non-RCU read side section.
So, pass lockdep_is_held(&trace_types_lock) to silence false lockdep
warning.

Link: https://lkml.kernel.org/r/20221227023036.784337-1-nashuiliang@gmail.com

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr")
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Chuang Wang 2022-12-27 10:30:36 +08:00 committed by Steven Rostedt (Google)
parent ac28d0a0f4
commit 685b64e4d6
1 changed files with 2 additions and 3 deletions
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5
kernel/trace/trace_osnoise.c
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@ -147,9 +147,8 @@ static void osnoise_unregister_instance(struct trace_array *tr)
* register/unregister serialization is provided by trace's
* trace_types_lock.
*/
lockdep_assert_held(&trace_types_lock);
list_for_each_entry_rcu(inst, &osnoise_instances, list) {
list_for_each_entry_rcu(inst, &osnoise_instances, list,
lockdep_is_held(&trace_types_lock)) {
if (inst->tr == tr) {
list_del_rcu(&inst->list);
found = 1;