From 549e914c96ae67760f36b9714b424dc992a0a69b Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Sat, 7 Jun 2025 10:28:21 -0400 Subject: [PATCH] tracing: Add rcu annotation around file->filter accesses Running sparse on trace_events_filter.c triggered several warnings about file->filter being accessed directly even though it's annotated with __rcu. Add rcu_dereference() around it and shuffle the logic slightly so that it's always referenced via accessor functions. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20250607102821.6c7effbf@gandalf.local.home Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_events_filter.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 711520081741..ea8b364b6818 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1250,7 +1250,9 @@ static void append_filter_err(struct trace_array *tr, static inline struct event_filter *event_filter(struct trace_event_file *file) { - return file->filter; + return rcu_dereference_protected(file->filter, + lockdep_is_held(&event_mutex)); + } /* caller must hold event_mutex */ @@ -1320,7 +1322,7 @@ void free_event_filter(struct event_filter *filter) static inline void __remove_filter(struct trace_event_file *file) { filter_disable(file); - remove_filter_string(file->filter); + remove_filter_string(event_filter(file)); } static void filter_free_subsystem_preds(struct trace_subsystem_dir *dir, @@ -1405,7 +1407,7 @@ static void try_delay_free_filter(struct event_filter *filter) static inline void __free_subsystem_filter(struct trace_event_file *file) { - __free_filter(file->filter); + __free_filter(event_filter(file)); file->filter = NULL; } @@ -1465,7 +1467,7 @@ static void filter_free_subsystem_filters(struct trace_subsystem_dir *dir, list_for_each_entry(file, &tr->events, list) { if (file->system != dir || !file->filter) continue; - __free_filter(file->filter); + __free_subsystem_filter(file); } __free_filter(filter); } -- 2.25.1