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tracing: Avoid adding tracer option before update_tracer_options

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[ 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>
This commit is contained in:
Mark-PK Tsai 2022-04-26 20:24:06 +08:00 committed by Greg Kroah-Hartman
parent 1788e6dbb6
commit 9e801c891a
1 changed files with 7 additions and 0 deletions
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7
kernel/trace/trace.c
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@ -5907,12 +5907,18 @@ 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);
}
@ -8649,6 +8655,7 @@ 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);
}