From 486fbcb3806c0c7a5dbeea326c4a146fd4ed4eff Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Tue, 11 Mar 2025 10:30:03 +0900 Subject: [PATCH] tracing: Skip update_last_data() if cleared and remove active check for save_mod() If the last boot data is already cleared, there is no reason to update it again. Skip if the TRACE_ARRAY_FL_LAST_BOOT is cleared. Also, for calling save_mod() when module loading, we don't need to check the trace is active or not because any module address can be on the stacktrace. Cc: Mark Rutland Cc: Mathieu Desnoyers Link: https://lore.kernel.org/174165660328.1173316.15529357882704817499.stgit@devnote2 Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 78ae76666695..382c7a562303 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6040,6 +6040,12 @@ static void update_last_data(struct trace_array *tr) if (!(tr->flags & TRACE_ARRAY_FL_BOOT)) return; + if (!(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) + return; + + /* Only if the buffer has previous boot data clear and update it. */ + tr->flags &= ~TRACE_ARRAY_FL_LAST_BOOT; + /* Reset the module list and reload them */ if (tr->scratch) { struct trace_scratch *tscratch = tr->scratch; @@ -6052,9 +6058,6 @@ static void update_last_data(struct trace_array *tr) module_for_each_mod(save_mod, tr); } - if (!(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) - return; - /* * Need to clear all CPU buffers as there cannot be events * from the previous boot mixed with events with this boot @@ -6077,7 +6080,6 @@ static void update_last_data(struct trace_array *tr) #else tscratch->kaslr_addr = 0; #endif - tr->flags &= ~TRACE_ARRAY_FL_LAST_BOOT; } /** @@ -10103,15 +10105,6 @@ static void trace_module_remove_evals(struct module *mod) static inline void trace_module_remove_evals(struct module *mod) { } #endif /* CONFIG_TRACE_EVAL_MAP_FILE */ -static bool trace_array_active(struct trace_array *tr) -{ - if (tr->current_trace != &nop_trace) - return true; - - /* 0 is no events, 1 is all disabled */ - return trace_events_enabled(tr, NULL) > 1; -} - static void trace_module_record(struct module *mod) { struct trace_array *tr; @@ -10120,11 +10113,8 @@ static void trace_module_record(struct module *mod) /* Update any persistent trace array that has already been started */ if ((tr->flags & (TRACE_ARRAY_FL_BOOT | TRACE_ARRAY_FL_LAST_BOOT)) == TRACE_ARRAY_FL_BOOT) { - /* Only update if the trace array is active */ - if (trace_array_active(tr)) { - guard(mutex)(&scratch_mutex); - save_mod(mod, tr); - } + guard(mutex)(&scratch_mutex); + save_mod(mod, tr); } } }