This is a note to let you know that I've just added the patch titled
tracing/osnoise: Use built-in RCU list checking
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-osnoise-use-built-in-rcu-list-checking.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a4ef8cfece510b7254754cb888d9d356dc873642
Author: Chuang Wang <nashuiliang@xxxxxxxxx>
Date: Tue Dec 27 10:30:36 2022 +0800
tracing/osnoise: Use built-in RCU list checking
[ Upstream commit 685b64e4d6da4be8b4595654a57db663b3d1dfc2 ]
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@xxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr")
Acked-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Signed-off-by: Chuang Wang <nashuiliang@xxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 4300c5dc4e5d..1c07efcb3d46 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -125,9 +125,8 @@ 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;
