tracing: Avoid adding tracer option before update_tracer_options
authorMark-PK Tsai <mark-pk.tsai@mediatek.com>
Tue, 26 Apr 2022 12:24:06 +0000 (20:24 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 14 Jun 2022 16:36:14 +0000 (18:36 +0200)
commit6eb85cbd9ef8fd47c1044284cb132cd8e6fe8ea4
tree431de58b0aaa77bbb1cdde9022eeecda5010b2c4
parent9b534640a2c6a8d88168febc82ec6d161184f2ec
tracing: Avoid adding tracer option before update_tracer_options

[ 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