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tracing: Have add_tracer_options() error pass up to callers

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The function add_tracer_options() can fail, but currently it is ignored.
Pass the status of add_tracer_options() up to adding a new tracer as well
as when an instance is created. Have the instance creation fail if the
add_tracer_options() fail.

Only print a warning for the top level instance, like it does with other
failures.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://patch.msgid.link/20251105161935.375299297@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
2025-11-05 11:19:11 -05:00
committed by Steven Rostedt (Google)
parent c7bed15ccf
commit 5aa0d18df0
1 changed files with 34 additions and 21 deletions
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55
kernel/trace/trace.c
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@@ -2302,7 +2302,7 @@ static inline int do_run_tracer_selftest(struct tracer *type)
}
#endif /* CONFIG_FTRACE_STARTUP_TEST */
static void add_tracer_options(struct trace_array *tr, struct tracer *t);
static int add_tracer_options(struct trace_array *tr, struct tracer *t);
static void __init apply_trace_boot_options(void);
@@ -2353,9 +2353,14 @@ int __init register_tracer(struct tracer *type)
if (ret < 0)
goto out;
ret = add_tracer_options(&global_trace, type);
if (ret < 0) {
pr_warn("Failed to create tracer options for %s\n", type->name);
goto out;
}
type->next = trace_types;
trace_types = type;
add_tracer_options(&global_trace, type);
out:
mutex_unlock(&trace_types_lock);
@@ -6221,7 +6226,7 @@ int tracing_update_buffers(struct trace_array *tr)
struct trace_option_dentry;
static void
static int
create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
/*
@@ -6243,17 +6248,17 @@ static void tracing_set_nop(struct trace_array *tr)
static bool tracer_options_updated;
static void add_tracer_options(struct trace_array *tr, struct tracer *t)
static int add_tracer_options(struct trace_array *tr, struct tracer *t)
{
/* Only enable if the directory has been created already. */
if (!tr->dir && !(tr->flags & TRACE_ARRAY_FL_GLOBAL))
return;
return 0;
/* Only create trace option files after update_tracer_options finish */
if (!tracer_options_updated)
return;
return 0;
create_trace_option_files(tr, t);
return create_trace_option_files(tr, t);
}
int tracing_set_tracer(struct trace_array *tr, const char *buf)
@@ -9585,7 +9590,7 @@ create_trace_option_file(struct trace_array *tr,
}
static void
static int
create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
{
struct trace_option_dentry *topts;
@@ -9596,24 +9601,24 @@ create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
int i;
if (!tracer)
return;
return 0;
flags = tracer->flags;
if (!flags || !flags->opts)
return;
return 0;
/*
* If this is an instance, only create flags for tracers
* the instance may have.
*/
if (!trace_ok_for_array(tracer, tr))
return;
return 0;
for (i = 0; i < tr->nr_topts; i++) {
/* Make sure there's no duplicate flags. */
if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
return;
return -EINVAL;
}
opts = flags->opts;
@@ -9623,13 +9628,13 @@ create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
if (!topts)
return;
return 0;
tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
GFP_KERNEL);
if (!tr_topts) {
kfree(topts);
return;
return -ENOMEM;
}
tr->topts = tr_topts;
@@ -9644,6 +9649,7 @@ create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
"Failed to create trace option: %s",
opts[cnt].name);
}
return 0;
}
static struct dentry *
@@ -10094,15 +10100,18 @@ static void init_trace_flags_index(struct trace_array *tr)
tr->trace_flags_index[i] = i;
}
static void __update_tracer_options(struct trace_array *tr)
static int __update_tracer_options(struct trace_array *tr)
{
struct tracer *t;
int ret = 0;
for (t = trace_types; t; t = t->next)
add_tracer_options(tr, t);
for (t = trace_types; t && !ret; t = t->next)
ret = add_tracer_options(tr, t);
return ret;
}
static void update_tracer_options(struct trace_array *tr)
static __init void update_tracer_options(struct trace_array *tr)
{
guard(mutex)(&trace_types_lock);
tracer_options_updated = true;
@@ -10151,9 +10160,13 @@ static int trace_array_create_dir(struct trace_array *tr)
}
init_tracer_tracefs(tr, tr->dir);
__update_tracer_options(tr);
return ret;
ret = __update_tracer_options(tr);
if (ret) {
event_trace_del_tracer(tr);
tracefs_remove(tr->dir);
return ret;
}
return 0;
}
static struct trace_array *