From: Mark-PK Tsai mark-pk.tsai@mediatek.com
[ Upstream commit ef9188bcc6ca1d8a2ad83e826b548e6820721061 ]
To prepare for support asynchronous tracer_init_tracefs initcall, avoid calling create_trace_option_files before __update_tracer_options. Otherwise, create_trace_option_files will show warning because some tracers in trace_types list are already in tr->topts.
For example, hwlat_tracer call register_tracer in late_initcall, and global_trace.dir is already created in tracing_init_dentry, hwlat_tracer will be put into tr->topts. Then if the __update_tracer_options is executed after hwlat_tracer registered, create_trace_option_files find that hwlat_tracer is already in tr->topts.
Link: https://lkml.kernel.org/r/20220426122407.17042-2-mark-pk.tsai@mediatek.com
Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/ Reported-by: kernel test robot oliver.sang@intel.com Signed-off-by: Mark-PK Tsai mark-pk.tsai@mediatek.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/trace.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 90e0fd5621da..de1638df2b09 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4798,12 +4798,18 @@ static void tracing_set_nop(struct trace_array *tr) tr->current_trace = &nop_trace; }
+static bool tracer_options_updated; + static void add_tracer_options(struct trace_array *tr, struct tracer *t) { /* Only enable if the directory has been created already. */ if (!tr->dir) return;
+ /* Only create trace option files after update_tracer_options finish */ + if (!tracer_options_updated) + return; + create_trace_option_files(tr, t); }
@@ -7082,6 +7088,7 @@ static void __update_tracer_options(struct trace_array *tr) static void update_tracer_options(struct trace_array *tr) { mutex_lock(&trace_types_lock); + tracer_options_updated = true; __update_tracer_options(tr); mutex_unlock(&trace_types_lock); }