Merge tag 'trace-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "The majority of the changes are for fixes and clean ups.

  Notable changes:

   - Rework trace event triggers code to be easier to interact with.

   - Support for embedding bootconfig with the kernel (as suppose to
     having it embedded in initram). This is useful for embedded boards
     without initram disks.

   - Speed up boot by parallelizing the creation of tracefs files.

   - Allow absolute ring buffer timestamps handle timestamps that use
     more than 59 bits.

   - Added new tracing clock "TAI" (International Atomic Time)

   - Have weak functions show up in available_filter_function list as:
     __ftrace_invalid_address___<invalid-offset> instead of using the
     name of the function before it"

* tag 'trace-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (52 commits)
  ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function
  tracing: Fix comments for event_trigger_separate_filter()
  x86/traceponit: Fix comment about irq vector tracepoints
  x86,tracing: Remove unused headers
  ftrace: Clean up hash direct_functions on register failures
  tracing: Fix comments of create_filter()
  tracing: Disable kcov on trace_preemptirq.c
  tracing: Initialize integer variable to prevent garbage return value
  ftrace: Fix typo in comment
  ftrace: Remove return value of ftrace_arch_modify_*()
  tracing: Cleanup code by removing init "char *name"
  tracing: Change "char *" string form to "char []"
  tracing/timerlat: Do not wakeup the thread if the trace stops at the IRQ
  tracing/timerlat: Print stacktrace in the IRQ handler if needed
  tracing/timerlat: Notify IRQ new max latency only if stop tracing is set
  kprobes: Fix build errors with CONFIG_KRETPROBES=n
  tracing: Fix return value of trace_pid_write()
  tracing: Fix potential double free in create_var_ref()
  tracing: Use strim() to remove whitespace instead of doing it manually
  ftrace: Deal with error return code of the ftrace_process_locs() function
  ...

1 files changed, 174 insertions, 36 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index f8db59c3a601..e750fe141a60 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -45,6 +45,8 @@
 #include "trace_output.h"
 #include "trace_stat.h"
 
+#define FTRACE_INVALID_FUNCTION		"__ftrace_invalid_address__"
+
 #define FTRACE_WARN_ON(cond)			\
 	({					\
 		int ___r = cond;		\
@@ -119,7 +121,7 @@ struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 struct ftrace_ops global_ops;
 
-/* Defined by vmlinux.lds.h see the commment above arch_ftrace_ops_list_func for details */
+/* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
 void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 			  struct ftrace_ops *op, struct ftrace_regs *fregs);
 
@@ -952,7 +954,6 @@ static struct tracer_stat function_stats __initdata = {
 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 {
 	struct ftrace_profile_stat *stat;
-	struct dentry *entry;
 	char *name;
 	int ret;
 	int cpu;
@@ -983,11 +984,9 @@ static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 		}
 	}
 
-	entry = tracefs_create_file("function_profile_enabled",
-				    TRACE_MODE_WRITE, d_tracer, NULL,
-				    &ftrace_profile_fops);
-	if (!entry)
-		pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
+	trace_create_file("function_profile_enabled",
+			  TRACE_MODE_WRITE, d_tracer, NULL,
+			  &ftrace_profile_fops);
 }
 
 #else /* CONFIG_FUNCTION_PROFILER */
@@ -2707,18 +2706,16 @@ ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
  * archs can override this function if they must do something
  * before the modifying code is performed.
  */
-int __weak ftrace_arch_code_modify_prepare(void)
+void __weak ftrace_arch_code_modify_prepare(void)
 {
-	return 0;
 }
 
 /*
  * archs can override this function if they must do something
  * after the modifying code is performed.
  */
-int __weak ftrace_arch_code_modify_post_process(void)
+void __weak ftrace_arch_code_modify_post_process(void)
 {
-	return 0;
 }
 
 void ftrace_modify_all_code(int command)
@@ -2804,12 +2801,7 @@ void __weak arch_ftrace_update_code(int command)
 
 static void ftrace_run_update_code(int command)
 {
-	int ret;
-
-	ret = ftrace_arch_code_modify_prepare();
-	FTRACE_WARN_ON(ret);
-	if (ret)
-		return;
+	ftrace_arch_code_modify_prepare();
 
 	/*
 	 * By default we use stop_machine() to modify the code.
@@ -2819,8 +2811,7 @@ static void ftrace_run_update_code(int command)
 	 */
 	arch_ftrace_update_code(command);
 
-	ret = ftrace_arch_code_modify_post_process();
-	FTRACE_WARN_ON(ret);
+	ftrace_arch_code_modify_post_process();
 }
 
 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
@@ -3631,6 +3622,105 @@ static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
 		seq_printf(m, " ->%pS", ptr);
 }
 
+#ifdef FTRACE_MCOUNT_MAX_OFFSET
+/*
+ * Weak functions can still have an mcount/fentry that is saved in
+ * the __mcount_loc section. These can be detected by having a
+ * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
+ * symbol found by kallsyms is not the function that the mcount/fentry
+ * is part of. The offset is much greater in these cases.
+ *
+ * Test the record to make sure that the ip points to a valid kallsyms
+ * and if not, mark it disabled.
+ */
+static int test_for_valid_rec(struct dyn_ftrace *rec)
+{
+	char str[KSYM_SYMBOL_LEN];
+	unsigned long offset;
+	const char *ret;
+
+	ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
+
+	/* Weak functions can cause invalid addresses */
+	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
+		rec->flags |= FTRACE_FL_DISABLED;
+		return 0;
+	}
+	return 1;
+}
+
+static struct workqueue_struct *ftrace_check_wq __initdata;
+static struct work_struct ftrace_check_work __initdata;
+
+/*
+ * Scan all the mcount/fentry entries to make sure they are valid.
+ */
+static __init void ftrace_check_work_func(struct work_struct *work)
+{
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec;
+
+	mutex_lock(&ftrace_lock);
+	do_for_each_ftrace_rec(pg, rec) {
+		test_for_valid_rec(rec);
+	} while_for_each_ftrace_rec();
+	mutex_unlock(&ftrace_lock);
+}
+
+static int __init ftrace_check_for_weak_functions(void)
+{
+	INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
+
+	ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
+
+	queue_work(ftrace_check_wq, &ftrace_check_work);
+	return 0;
+}
+
+static int __init ftrace_check_sync(void)
+{
+	/* Make sure the ftrace_check updates are finished */
+	if (ftrace_check_wq)
+		destroy_workqueue(ftrace_check_wq);
+	return 0;
+}
+
+late_initcall_sync(ftrace_check_sync);
+subsys_initcall(ftrace_check_for_weak_functions);
+
+static int print_rec(struct seq_file *m, unsigned long ip)
+{
+	unsigned long offset;
+	char str[KSYM_SYMBOL_LEN];
+	char *modname;
+	const char *ret;
+
+	ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
+	/* Weak functions can cause invalid addresses */
+	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
+		snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
+			 FTRACE_INVALID_FUNCTION, offset);
+		ret = NULL;
+	}
+
+	seq_puts(m, str);
+	if (modname)
+		seq_printf(m, " [%s]", modname);
+	return ret == NULL ? -1 : 0;
+}
+#else
+static inline int test_for_valid_rec(struct dyn_ftrace *rec)
+{
+	return 1;
+}
+
+static inline int print_rec(struct seq_file *m, unsigned long ip)
+{
+	seq_printf(m, "%ps", (void *)ip);
+	return 0;
+}
+#endif
+
 static int t_show(struct seq_file *m, void *v)
 {
 	struct ftrace_iterator *iter = m->private;
@@ -3655,7 +3745,13 @@ static int t_show(struct seq_file *m, void *v)
 	if (!rec)
 		return 0;
 
-	seq_printf(m, "%ps", (void *)rec->ip);
+	if (print_rec(m, rec->ip)) {
+		/* This should only happen when a rec is disabled */
+		WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
+		seq_putc(m, '\n');
+		return 0;
+	}
+
 	if (iter->flags & FTRACE_ITER_ENABLED) {
 		struct ftrace_ops *ops;
 
@@ -3973,6 +4069,24 @@ add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
 	return 0;
 }
 
+#ifdef FTRACE_MCOUNT_MAX_OFFSET
+static int lookup_ip(unsigned long ip, char **modname, char *str)
+{
+	unsigned long offset;
+
+	kallsyms_lookup(ip, NULL, &offset, modname, str);
+	if (offset > FTRACE_MCOUNT_MAX_OFFSET)
+		return -1;
+	return 0;
+}
+#else
+static int lookup_ip(unsigned long ip, char **modname, char *str)
+{
+	kallsyms_lookup(ip, NULL, NULL, modname, str);
+	return 0;
+}
+#endif
+
 static int
 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
 		struct ftrace_glob *mod_g, int exclude_mod)
@@ -3980,7 +4094,12 @@ ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
 	char str[KSYM_SYMBOL_LEN];
 	char *modname;
 
-	kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
+	if (lookup_ip(rec->ip, &modname, str)) {
+		/* This should only happen when a rec is disabled */
+		WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
+			     !(rec->flags & FTRACE_FL_DISABLED));
+		return 0;
+	}
 
 	if (mod_g) {
 		int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
@@ -4431,7 +4550,7 @@ int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
  * @ip: The instruction pointer address to remove the data from
  *
  * Returns the data if it is found, otherwise NULL.
- * Note, if the data pointer is used as the data itself, (see 
+ * Note, if the data pointer is used as the data itself, (see
  * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
  * if the data pointer was set to zero.
  */
@@ -4526,8 +4645,8 @@ register_ftrace_function_probe(char *glob, struct trace_array *tr,
 			       struct ftrace_probe_ops *probe_ops,
 			       void *data)
 {
+	struct ftrace_func_probe *probe = NULL, *iter;
 	struct ftrace_func_entry *entry;
-	struct ftrace_func_probe *probe;
 	struct ftrace_hash **orig_hash;
 	struct ftrace_hash *old_hash;
 	struct ftrace_hash *hash;
@@ -4546,11 +4665,13 @@ register_ftrace_function_probe(char *glob, struct trace_array *tr,
 
 	mutex_lock(&ftrace_lock);
 	/* Check if the probe_ops is already registered */
-	list_for_each_entry(probe, &tr->func_probes, list) {
-		if (probe->probe_ops == probe_ops)
+	list_for_each_entry(iter, &tr->func_probes, list) {
+		if (iter->probe_ops == probe_ops) {
+			probe = iter;
 			break;
+		}
 	}
-	if (&probe->list == &tr->func_probes) {
+	if (!probe) {
 		probe = kzalloc(sizeof(*probe), GFP_KERNEL);
 		if (!probe) {
 			mutex_unlock(&ftrace_lock);
@@ -4668,9 +4789,9 @@ int
 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
 				      struct ftrace_probe_ops *probe_ops)
 {
+	struct ftrace_func_probe *probe = NULL, *iter;
 	struct ftrace_ops_hash old_hash_ops;
 	struct ftrace_func_entry *entry;
-	struct ftrace_func_probe *probe;
 	struct ftrace_glob func_g;
 	struct ftrace_hash **orig_hash;
 	struct ftrace_hash *old_hash;
@@ -4698,11 +4819,13 @@ unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
 
 	mutex_lock(&ftrace_lock);
 	/* Check if the probe_ops is already registered */
-	list_for_each_entry(probe, &tr->func_probes, list) {
-		if (probe->probe_ops == probe_ops)
+	list_for_each_entry(iter, &tr->func_probes, list) {
+		if (iter->probe_ops == probe_ops) {
+			probe = iter;
 			break;
+		}
 	}
-	if (&probe->list == &tr->func_probes)
+	if (!probe)
 		goto err_unlock_ftrace;
 
 	ret = -EINVAL;
@@ -5161,8 +5284,6 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr)
 		goto out_unlock;
 
 	ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
-	if (ret)
-		remove_hash_entry(direct_functions, entry);
 
 	if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
 		ret = register_ftrace_function(&direct_ops);
@@ -5171,6 +5292,7 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr)
 	}
 
 	if (ret) {
+		remove_hash_entry(direct_functions, entry);
 		kfree(entry);
 		if (!direct->count) {
 			list_del_rcu(&direct->next);
@@ -6793,6 +6915,13 @@ void ftrace_module_enable(struct module *mod)
 		    !within_module_init(rec->ip, mod))
 			break;
 
+		/* Weak functions should still be ignored */
+		if (!test_for_valid_rec(rec)) {
+			/* Clear all other flags. Should not be enabled anyway */
+			rec->flags = FTRACE_FL_DISABLED;
+			continue;
+		}
+
 		cnt = 0;
 
 		/*
@@ -6829,11 +6958,16 @@ void ftrace_module_enable(struct module *mod)
 
 void ftrace_module_init(struct module *mod)
 {
+	int ret;
+
 	if (ftrace_disabled || !mod->num_ftrace_callsites)
 		return;
 
-	ftrace_process_locs(mod, mod->ftrace_callsites,
-			    mod->ftrace_callsites + mod->num_ftrace_callsites);
+	ret = ftrace_process_locs(mod, mod->ftrace_callsites,
+				  mod->ftrace_callsites + mod->num_ftrace_callsites);
+	if (ret)
+		pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
+			mod->name);
 }
 
 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
@@ -7166,15 +7300,19 @@ void __init ftrace_init(void)
 	pr_info("ftrace: allocating %ld entries in %ld pages\n",
 		count, count / ENTRIES_PER_PAGE + 1);
 
-	last_ftrace_enabled = ftrace_enabled = 1;
-
 	ret = ftrace_process_locs(NULL,
 				  __start_mcount_loc,
 				  __stop_mcount_loc);
+	if (ret) {
+		pr_warn("ftrace: failed to allocate entries for functions\n");
+		goto failed;
+	}
 
 	pr_info("ftrace: allocated %ld pages with %ld groups\n",
 		ftrace_number_of_pages, ftrace_number_of_groups);
 
+	last_ftrace_enabled = ftrace_enabled = 1;
+
 	set_ftrace_early_filters();
 
 	return;