Merge tag 'trace-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Cleanup with guard() and free() helpers

   There were several places in the code that had a lot of "goto out" in
   the error paths to either unlock a lock or free some memory that was
   allocated. But this is error prone. Convert the code over to use the
   guard() and free() helpers that let the compiler unlock locks or free
   memory when the function exits.

 - Update the Rust tracepoint code to use the C code too

   There was some duplication of the tracepoint code for Rust that did
   the same logic as the C code. Add a helper that makes it possible for
   both algorithms to use the same logic in one place.

 - Add poll to trace event hist files

   It is useful to know when an event is triggered, or even with some
   filtering. Since hist files of events get updated when active and the
   event is triggered, allow applications to poll the hist file and wake
   up when an event is triggered. This will let the application know
   that the event it is waiting for happened.

 - Add :mod: command to enable events for current or future modules

   The function tracer already has a way to enable functions to be
   traced in modules by writing ":mod:<module>" into set_ftrace_filter.
   That will enable either all the functions for the module if it is
   loaded, or if it is not, it will cache that command, and when the
   module is loaded that matches <module>, its functions will be
   enabled. This also allows init functions to be traced. But currently
   events do not have that feature.

   Add the command where if ':mod:<module>' is written into set_event,
   then either all the modules events are enabled if it is loaded, or
   cache it so that the module's events are enabled when it is loaded.
   This also works from the kernel command line, where
   "trace_event=:mod:<module>", when the module is loaded at boot up,
   its events will be enabled then.

* tag 'trace-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (26 commits)
  tracing: Fix output of set_event for some cached module events
  tracing: Fix allocation of printing set_event file content
  tracing: Rename update_cache() to update_mod_cache()
  tracing: Fix #if CONFIG_MODULES to #ifdef CONFIG_MODULES
  selftests/ftrace: Add test that tests event :mod: commands
  tracing: Cache ":mod:" events for modules not loaded yet
  tracing: Add :mod: command to enabled module events
  selftests/tracing: Add hist poll() support test
  tracing/hist: Support POLLPRI event for poll on histogram
  tracing/hist: Add poll(POLLIN) support on hist file
  tracing: Fix using ret variable in tracing_set_tracer()
  tracepoint: Reduce duplication of __DO_TRACE_CALL
  tracing/string: Create and use __free(argv_free) in trace_dynevent.c
  tracing: Switch trace_stat.c code over to use guard()
  tracing: Switch trace_stack.c code over to use guard()
  tracing: Switch trace_osnoise.c code over to use guard() and __free()
  tracing: Switch trace_events_synth.c code over to use guard()
  tracing: Switch trace_events_filter.c code over to use guard()
  tracing: Switch trace_events_trigger.c code over to use guard()
  tracing: Switch trace_events_hist.c code over to use guard()
  ...

1 files changed, 123 insertions, 174 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2542ec398b5d..1496a5ac33ae 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -26,6 +26,7 @@
 #include <linux/hardirq.h>
 #include <linux/linkage.h>
 #include <linux/uaccess.h>
+#include <linux/cleanup.h>
 #include <linux/vmalloc.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
@@ -535,19 +536,16 @@ LIST_HEAD(ftrace_trace_arrays);
 int trace_array_get(struct trace_array *this_tr)
 {
 	struct trace_array *tr;
-	int ret = -ENODEV;
 
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
 	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
 		if (tr == this_tr) {
 			tr->ref++;
-			ret = 0;
-			break;
+			return 0;
 		}
 	}
-	mutex_unlock(&trace_types_lock);
 
-	return ret;
+	return -ENODEV;
 }
 
 static void __trace_array_put(struct trace_array *this_tr)
@@ -1443,22 +1441,20 @@ EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
 int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
 				 cond_update_fn_t update)
 {
-	struct cond_snapshot *cond_snapshot;
-	int ret = 0;
+	struct cond_snapshot *cond_snapshot __free(kfree) =
+		kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
+	int ret;
 
-	cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
 	if (!cond_snapshot)
 		return -ENOMEM;
 
 	cond_snapshot->cond_data = cond_data;
 	cond_snapshot->update = update;
 
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
 
-	if (tr->current_trace->use_max_tr) {
-		ret = -EBUSY;
-		goto fail_unlock;
-	}
+	if (tr->current_trace->use_max_tr)
+		return -EBUSY;
 
 	/*
 	 * The cond_snapshot can only change to NULL without the
@@ -1468,29 +1464,20 @@ int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
 	 * do safely with only holding the trace_types_lock and not
 	 * having to take the max_lock.
 	 */
-	if (tr->cond_snapshot) {
-		ret = -EBUSY;
-		goto fail_unlock;
-	}
+	if (tr->cond_snapshot)
+		return -EBUSY;
 
 	ret = tracing_arm_snapshot_locked(tr);
 	if (ret)
-		goto fail_unlock;
+		return ret;
 
 	local_irq_disable();
 	arch_spin_lock(&tr->max_lock);
-	tr->cond_snapshot = cond_snapshot;
+	tr->cond_snapshot = no_free_ptr(cond_snapshot);
 	arch_spin_unlock(&tr->max_lock);
 	local_irq_enable();
 
-	mutex_unlock(&trace_types_lock);
-
-	return ret;
-
- fail_unlock:
-	mutex_unlock(&trace_types_lock);
-	kfree(cond_snapshot);
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
 
@@ -2203,10 +2190,10 @@ static __init int init_trace_selftests(void)
 
 	selftests_can_run = true;
 
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
 
 	if (list_empty(&postponed_selftests))
-		goto out;
+		return 0;
 
 	pr_info("Running postponed tracer tests:\n");
 
@@ -2235,9 +2222,6 @@ static __init int init_trace_selftests(void)
 	}
 	tracing_selftest_running = false;
 
- out:
-	mutex_unlock(&trace_types_lock);
-
 	return 0;
 }
 core_initcall(init_trace_selftests);
@@ -2807,7 +2791,7 @@ int tracepoint_printk_sysctl(const struct ctl_table *table, int write,
 	int save_tracepoint_printk;
 	int ret;
 
-	mutex_lock(&tracepoint_printk_mutex);
+	guard(mutex)(&tracepoint_printk_mutex);
 	save_tracepoint_printk = tracepoint_printk;
 
 	ret = proc_dointvec(table, write, buffer, lenp, ppos);
@@ -2820,16 +2804,13 @@ int tracepoint_printk_sysctl(const struct ctl_table *table, int write,
 		tracepoint_printk = 0;
 
 	if (save_tracepoint_printk == tracepoint_printk)
-		goto out;
+		return ret;
 
 	if (tracepoint_printk)
 		static_key_enable(&tracepoint_printk_key.key);
 	else
 		static_key_disable(&tracepoint_printk_key.key);
 
- out:
-	mutex_unlock(&tracepoint_printk_mutex);
-
 	return ret;
 }
 
@@ -5127,7 +5108,8 @@ static int tracing_trace_options_show(struct seq_file *m, void *v)
 	u32 tracer_flags;
 	int i;
 
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
+
 	tracer_flags = tr->current_trace->flags->val;
 	trace_opts = tr->current_trace->flags->opts;
 
@@ -5144,7 +5126,6 @@ static int tracing_trace_options_show(struct seq_file *m, void *v)
 		else
 			seq_printf(m, "no%s\n", trace_opts[i].name);
 	}
-	mutex_unlock(&trace_types_lock);
 
 	return 0;
 }
@@ -5537,6 +5518,8 @@ static const char readme_msg[] =
 	"\t    efield: For event probes ('e' types), the field is on of the fields\n"
 	"\t            of the <attached-group>/<attached-event>.\n"
 #endif
+	"  set_event\t\t- Enables events by name written into it\n"
+	"\t\t\t  Can enable module events via: :mod:<module>\n"
 	"  events/\t\t- Directory containing all trace event subsystems:\n"
 	"      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
 	"  events/<system>/\t- Directory containing all trace events for <system>:\n"
@@ -5809,7 +5792,7 @@ trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
 		return;
 	}
 
-	mutex_lock(&trace_eval_mutex);
+	guard(mutex)(&trace_eval_mutex);
 
 	if (!trace_eval_maps)
 		trace_eval_maps = map_array;
@@ -5833,8 +5816,6 @@ trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
 		map_array++;
 	}
 	memset(map_array, 0, sizeof(*map_array));
-
-	mutex_unlock(&trace_eval_mutex);
 }
 
 static void trace_create_eval_file(struct dentry *d_tracer)
@@ -5998,23 +5979,18 @@ ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
 {
 	int ret;
 
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
 
 	if (cpu_id != RING_BUFFER_ALL_CPUS) {
 		/* make sure, this cpu is enabled in the mask */
-		if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
-			ret = -EINVAL;
-			goto out;
-		}
+		if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask))
+			return -EINVAL;
 	}
 
 	ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
 	if (ret < 0)
 		ret = -ENOMEM;
 
-out:
-	mutex_unlock(&trace_types_lock);
-
 	return ret;
 }
 
@@ -6106,9 +6082,9 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
 #ifdef CONFIG_TRACER_MAX_TRACE
 	bool had_max_tr;
 #endif
-	int ret = 0;
+	int ret;
 
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
 
 	update_last_data(tr);
 
@@ -6116,7 +6092,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
 		ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
 						RING_BUFFER_ALL_CPUS);
 		if (ret < 0)
-			goto out;
+			return ret;
 		ret = 0;
 	}
 
@@ -6124,43 +6100,37 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
 		if (strcmp(t->name, buf) == 0)
 			break;
 	}
-	if (!t) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (!t)
+		return -EINVAL;
+
 	if (t == tr->current_trace)
-		goto out;
+		return 0;
 
 #ifdef CONFIG_TRACER_SNAPSHOT
 	if (t->use_max_tr) {
 		local_irq_disable();
 		arch_spin_lock(&tr->max_lock);
-		if (tr->cond_snapshot)
-			ret = -EBUSY;
+		ret = tr->cond_snapshot ? -EBUSY : 0;
 		arch_spin_unlock(&tr->max_lock);
 		local_irq_enable();
 		if (ret)
-			goto out;
+			return ret;
 	}
 #endif
 	/* Some tracers won't work on kernel command line */
 	if (system_state < SYSTEM_RUNNING && t->noboot) {
 		pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
 			t->name);
-		goto out;
+		return -EINVAL;
 	}
 
 	/* Some tracers are only allowed for the top level buffer */
-	if (!trace_ok_for_array(t, tr)) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (!trace_ok_for_array(t, tr))
+		return -EINVAL;
 
 	/* If trace pipe files are being read, we can't change the tracer */
-	if (tr->trace_ref) {
-		ret = -EBUSY;
-		goto out;
-	}
+	if (tr->trace_ref)
+		return -EBUSY;
 
 	trace_branch_disable();
 
@@ -6191,7 +6161,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
 	if (!had_max_tr && t->use_max_tr) {
 		ret = tracing_arm_snapshot_locked(tr);
 		if (ret)
-			goto out;
+			return ret;
 	}
 #else
 	tr->current_trace = &nop_trace;
@@ -6204,17 +6174,15 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
 			if (t->use_max_tr)
 				tracing_disarm_snapshot(tr);
 #endif
-			goto out;
+			return ret;
 		}
 	}
 
 	tr->current_trace = t;
 	tr->current_trace->enabled++;
 	trace_branch_enable(tr);
- out:
-	mutex_unlock(&trace_types_lock);
 
-	return ret;
+	return 0;
 }
 
 static ssize_t
@@ -6292,22 +6260,18 @@ tracing_thresh_write(struct file *filp, const char __user *ubuf,
 	struct trace_array *tr = filp->private_data;
 	int ret;
 
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
 	ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
 	if (ret < 0)
-		goto out;
+		return ret;
 
 	if (tr->current_trace->update_thresh) {
 		ret = tr->current_trace->update_thresh(tr);
 		if (ret < 0)
-			goto out;
+			return ret;
 	}
 
-	ret = cnt;
-out:
-	mutex_unlock(&trace_types_lock);
-
-	return ret;
+	return cnt;
 }
 
 #ifdef CONFIG_TRACER_MAX_TRACE
@@ -6526,31 +6490,29 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
 	 * This is just a matter of traces coherency, the ring buffer itself
 	 * is protected.
 	 */
-	mutex_lock(&iter->mutex);
+	guard(mutex)(&iter->mutex);
 
 	/* return any leftover data */
 	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
 	if (sret != -EBUSY)
-		goto out;
+		return sret;
 
 	trace_seq_init(&iter->seq);
 
 	if (iter->trace->read) {
 		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
 		if (sret)
-			goto out;
+			return sret;
 	}
 
 waitagain:
 	sret = tracing_wait_pipe(filp);
 	if (sret <= 0)
-		goto out;
+		return sret;
 
 	/* stop when tracing is finished */
-	if (trace_empty(iter)) {
-		sret = 0;
-		goto out;
-	}
+	if (trace_empty(iter))
+		return 0;
 
 	if (cnt >= TRACE_SEQ_BUFFER_SIZE)
 		cnt = TRACE_SEQ_BUFFER_SIZE - 1;
@@ -6614,9 +6576,6 @@ waitagain:
 	if (sret == -EBUSY)
 		goto waitagain;
 
-out:
-	mutex_unlock(&iter->mutex);
-
 	return sret;
 }
 
@@ -7208,25 +7167,19 @@ u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_eve
  */
 int tracing_set_filter_buffering(struct trace_array *tr, bool set)
 {
-	int ret = 0;
-
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
 
 	if (set && tr->no_filter_buffering_ref++)
-		goto out;
+		return 0;
 
 	if (!set) {
-		if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
-			ret = -EINVAL;
-			goto out;
-		}
+		if (WARN_ON_ONCE(!tr->no_filter_buffering_ref))
+			return -EINVAL;
 
 		--tr->no_filter_buffering_ref;
 	}
- out:
-	mutex_unlock(&trace_types_lock);
 
-	return ret;
+	return 0;
 }
 
 struct ftrace_buffer_info {
@@ -7302,12 +7255,10 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	if (ret)
 		return ret;
 
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&trace_types_lock);
 
-	if (tr->current_trace->use_max_tr) {
-		ret = -EBUSY;
-		goto out;
-	}
+	if (tr->current_trace->use_max_tr)
+		return -EBUSY;
 
 	local_irq_disable();
 	arch_spin_lock(&tr->max_lock);
@@ -7316,24 +7267,20 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	arch_spin_unlock(&tr->max_lock);
 	local_irq_enable();
 	if (ret)
-		goto out;
+		return ret;
 
 	switch (val) {
 	case 0:
-		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
-			ret = -EINVAL;
-			break;
-		}
+		if (iter->cpu_file != RING_BUFFER_ALL_CPUS)
+			return -EINVAL;
 		if (tr->allocated_snapshot)
 			free_snapshot(tr);
 		break;
 	case 1:
 /* Only allow per-cpu swap if the ring buffer supports it */
 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
-		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
-			ret = -EINVAL;
-			break;
-		}
+		if (iter->cpu_file != RING_BUFFER_ALL_CPUS)
+			return -EINVAL;
 #endif
 		if (tr->allocated_snapshot)
 			ret = resize_buffer_duplicate_size(&tr->max_buffer,
@@ -7341,7 +7288,7 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
 
 		ret = tracing_arm_snapshot_locked(tr);
 		if (ret)
-			break;
+			return ret;
 
 		/* Now, we're going to swap */
 		if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
@@ -7368,8 +7315,7 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
 		*ppos += cnt;
 		ret = cnt;
 	}
-out:
-	mutex_unlock(&trace_types_lock);
+
 	return ret;
 }
 
@@ -7755,12 +7701,11 @@ void tracing_log_err(struct trace_array *tr,
 
 	len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1;
 
-	mutex_lock(&tracing_err_log_lock);
+	guard(mutex)(&tracing_err_log_lock);
+
 	err = get_tracing_log_err(tr, len);
-	if (PTR_ERR(err) == -ENOMEM) {
-		mutex_unlock(&tracing_err_log_lock);
+	if (PTR_ERR(err) == -ENOMEM)
 		return;
-	}
 
 	snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
 	snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd);
@@ -7771,7 +7716,6 @@ void tracing_log_err(struct trace_array *tr,
 	err->info.ts = local_clock();
 
 	list_add_tail(&err->list, &tr->err_log);
-	mutex_unlock(&tracing_err_log_lock);
 }
 
 static void clear_tracing_err_log(struct trace_array *tr)
@@ -9467,6 +9411,10 @@ trace_array_create_systems(const char *name, const char *systems,
 	INIT_LIST_HEAD(&tr->hist_vars);
 	INIT_LIST_HEAD(&tr->err_log);
 
+#ifdef CONFIG_MODULES
+	INIT_LIST_HEAD(&tr->mod_events);
+#endif
+
 	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
 		goto out_free_tr;
 
@@ -9515,20 +9463,17 @@ static int instance_mkdir(const char *name)
 	struct trace_array *tr;
 	int ret;
 
-	mutex_lock(&event_mutex);
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&event_mutex);
+	guard(mutex)(&trace_types_lock);
 
 	ret = -EEXIST;
 	if (trace_array_find(name))
-		goto out_unlock;
+		return -EEXIST;
 
 	tr = trace_array_create(name);
 
 	ret = PTR_ERR_OR_ZERO(tr);
 
-out_unlock:
-	mutex_unlock(&trace_types_lock);
-	mutex_unlock(&event_mutex);
 	return ret;
 }
 
@@ -9578,24 +9523,23 @@ struct trace_array *trace_array_get_by_name(const char *name, const char *system
 {
 	struct trace_array *tr;
 
-	mutex_lock(&event_mutex);
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&event_mutex);
+	guard(mutex)(&trace_types_lock);
 
 	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
-		if (tr->name && strcmp(tr->name, name) == 0)
-			goto out_unlock;
+		if (tr->name && strcmp(tr->name, name) == 0) {
+			tr->ref++;
+			return tr;
+		}
 	}
 
 	tr = trace_array_create_systems(name, systems, 0, 0);
 
 	if (IS_ERR(tr))
 		tr = NULL;
-out_unlock:
-	if (tr)
+	else
 		tr->ref++;
 
-	mutex_unlock(&trace_types_lock);
-	mutex_unlock(&event_mutex);
 	return tr;
 }
 EXPORT_SYMBOL_GPL(trace_array_get_by_name);
@@ -9646,48 +9590,36 @@ static int __remove_instance(struct trace_array *tr)
 int trace_array_destroy(struct trace_array *this_tr)
 {
 	struct trace_array *tr;
-	int ret;
 
 	if (!this_tr)
 		return -EINVAL;
 
-	mutex_lock(&event_mutex);
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&event_mutex);
+	guard(mutex)(&trace_types_lock);
 
-	ret = -ENODEV;
 
 	/* Making sure trace array exists before destroying it. */
 	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
-		if (tr == this_tr) {
-			ret = __remove_instance(tr);
-			break;
-		}
+		if (tr == this_tr)
+			return __remove_instance(tr);
 	}
 
-	mutex_unlock(&trace_types_lock);
-	mutex_unlock(&event_mutex);
-
-	return ret;
+	return -ENODEV;
 }
 EXPORT_SYMBOL_GPL(trace_array_destroy);
 
 static int instance_rmdir(const char *name)
 {
 	struct trace_array *tr;
-	int ret;
 
-	mutex_lock(&event_mutex);
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&event_mutex);
+	guard(mutex)(&trace_types_lock);
 
-	ret = -ENODEV;
 	tr = trace_array_find(name);
-	if (tr)
-		ret = __remove_instance(tr);
-
-	mutex_unlock(&trace_types_lock);
-	mutex_unlock(&event_mutex);
+	if (!tr)
+		return -ENODEV;
 
-	return ret;
+	return __remove_instance(tr);
 }
 
 static __init void create_trace_instances(struct dentry *d_tracer)
@@ -9700,19 +9632,16 @@ static __init void create_trace_instances(struct dentry *d_tracer)
 	if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
 		return;
 
-	mutex_lock(&event_mutex);
-	mutex_lock(&trace_types_lock);
+	guard(mutex)(&event_mutex);
+	guard(mutex)(&trace_types_lock);
 
 	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
 		if (!tr->name)
 			continue;
 		if (MEM_FAIL(trace_array_create_dir(tr) < 0,
 			     "Failed to create instance directory\n"))
-			break;
+			return;
 	}
-
-	mutex_unlock(&trace_types_lock);
-	mutex_unlock(&event_mutex);
 }
 
 static void
@@ -9902,6 +9831,24 @@ late_initcall_sync(trace_eval_sync);
 
 
 #ifdef CONFIG_MODULES
+
+bool module_exists(const char *module)
+{
+	/* All modules have the symbol __this_module */
+	static const char this_mod[] = "__this_module";
+	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
+	unsigned long val;
+	int n;
+
+	n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
+
+	if (n > sizeof(modname) - 1)
+		return false;
+
+	val = module_kallsyms_lookup_name(modname);
+	return val != 0;
+}
+
 static void trace_module_add_evals(struct module *mod)
 {
 	if (!mod->num_trace_evals)
@@ -9926,7 +9873,7 @@ static void trace_module_remove_evals(struct module *mod)
 	if (!mod->num_trace_evals)
 		return;
 
-	mutex_lock(&trace_eval_mutex);
+	guard(mutex)(&trace_eval_mutex);
 
 	map = trace_eval_maps;
 
@@ -9938,12 +9885,10 @@ static void trace_module_remove_evals(struct module *mod)
 		map = map->tail.next;
 	}
 	if (!map)
-		goto out;
+		return;
 
 	*last = trace_eval_jmp_to_tail(map)->tail.next;
 	kfree(map);
- out:
-	mutex_unlock(&trace_eval_mutex);
 }
 #else
 static inline void trace_module_remove_evals(struct module *mod) { }
@@ -10616,6 +10561,10 @@ __init static int tracer_alloc_buffers(void)
 #endif
 	ftrace_init_global_array_ops(&global_trace);
 
+#ifdef CONFIG_MODULES
+	INIT_LIST_HEAD(&global_trace.mod_events);
+#endif
+
 	init_trace_flags_index(&global_trace);
 
 	register_tracer(&nop_trace);