Messages in this thread Patch in this message | | | From | Mark-PK Tsai <> | Subject | [PATCH v3 1/2] tracing: Avoid adding tracer option before update_tracer_options | Date | Wed, 23 Mar 2022 23:22:56 +0800 |
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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://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> --- kernel/trace/trace.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index eb44418574f9..85ec758c4455 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6317,12 +6317,18 @@ 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); } @@ -9133,6 +9139,7 @@ static void update_tracer_options(struct trace_array *tr) { mutex_lock(&trace_types_lock); __update_tracer_options(tr); + tracer_options_updated = true; mutex_unlock(&trace_types_lock); } -- 2.18.0
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