Merge tag 'ftrace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ftrace updates from Steven Rostedt:

 - Keep track of when fgraph_ops are registered or not

   Keep accounting of when fgraph_ops are registered as if a fgraph_ops
   is registered twice it can mess up the accounting and it will not
   work as expected later. Trigger a warning if something registers it
   twice as to catch bugs before they are found by things just not
   working as expected.

 - Make DYNAMIC_FTRACE always enabled for architectures that support it

   As static ftrace (where all functions are always traced) is very
   expensive and only exists to help architectures support ftrace, do
   not make it an option. As soon as an architecture supports
   DYNAMIC_FTRACE make it use it. This simplifies the code.

 - Remove redundant config HAVE_FTRACE_MCOUNT_RECORD

   The CONFIG_HAVE_FTRACE_MCOUNT was added to help simplify the
   DYNAMIC_FTRACE work, but now every architecture that implements
   DYNAMIC_FTRACE also has HAVE_FTRACE_MCOUNT set too, making it
   redundant with the HAVE_DYNAMIC_FTRACE.

 - Make pid_ptr string size match the comment

   In print_graph_proc() the pid_ptr string is of size 11, but the
   comment says /* sign + log10(MAX_INT) + '\0' */ which is actually 12.

* tag 'ftrace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Remove redundant config HAVE_FTRACE_MCOUNT_RECORD
  ftrace: Make DYNAMIC_FTRACE always enabled for architectures that support it
  fgraph: Keep track of when fgraph_ops are registered or not
  fgraph: Make pid_str size match the comment

5 files changed, 20 insertions, 24 deletions

diff --git a/kernel/module/main.c b/kernel/module/main.c
index cdcc50a5353d..81f9df8859dc 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2673,7 +2673,7 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 					 sizeof(*mod->trace_bprintk_fmt_start),
 					 &mod->num_trace_bprintk_fmt);
 #endif
-#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+#ifdef CONFIG_DYNAMIC_FTRACE
 	/* sechdrs[0].sh_size is always zero */
 	mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION,
 					     sizeof(*mod->ftrace_callsites),
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index a3f35c7d83b6..9f2b1661a8ac 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -74,11 +74,6 @@ config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
 	  If the architecture generates __patchable_function_entries sections
 	  but does not want them included in the ftrace locations.
 
-config HAVE_FTRACE_MCOUNT_RECORD
-	bool
-	help
-	  See Documentation/trace/ftrace-design.rst
-
 config HAVE_SYSCALL_TRACEPOINTS
 	bool
 	help
@@ -275,7 +270,7 @@ config FUNCTION_TRACE_ARGS
 	  funcgraph-args (for the function graph tracer)
 
 config DYNAMIC_FTRACE
-	bool "enable/disable function tracing dynamically"
+	bool
 	depends on FUNCTION_TRACER
 	depends on HAVE_DYNAMIC_FTRACE
 	default y
@@ -803,27 +798,22 @@ config BPF_KPROBE_OVERRIDE
 	 Allows BPF to override the execution of a probed function and
 	 set a different return value.  This is used for error injection.
 
-config FTRACE_MCOUNT_RECORD
-	def_bool y
-	depends on DYNAMIC_FTRACE
-	depends on HAVE_FTRACE_MCOUNT_RECORD
-
 config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 	bool
-	depends on FTRACE_MCOUNT_RECORD
+	depends on DYNAMIC_FTRACE
 
 config FTRACE_MCOUNT_USE_CC
 	def_bool y
 	depends on $(cc-option,-mrecord-mcount)
 	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
-	depends on FTRACE_MCOUNT_RECORD
+	depends on DYNAMIC_FTRACE
 
 config FTRACE_MCOUNT_USE_OBJTOOL
 	def_bool y
 	depends on HAVE_OBJTOOL_MCOUNT
 	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 	depends on !FTRACE_MCOUNT_USE_CC
-	depends on FTRACE_MCOUNT_RECORD
+	depends on DYNAMIC_FTRACE
 	select OBJTOOL
 
 config FTRACE_MCOUNT_USE_RECORDMCOUNT
@@ -831,7 +821,7 @@ config FTRACE_MCOUNT_USE_RECORDMCOUNT
 	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 	depends on !FTRACE_MCOUNT_USE_CC
 	depends on !FTRACE_MCOUNT_USE_OBJTOOL
-	depends on FTRACE_MCOUNT_RECORD
+	depends on DYNAMIC_FTRACE
 
 config TRACING_MAP
 	bool
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index c5b207992fb4..f4d200f0c610 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -1325,6 +1325,10 @@ int register_ftrace_graph(struct fgraph_ops *gops)
 	int ret = 0;
 	int i = -1;
 
+	if (WARN_ONCE(gops->ops.flags & FTRACE_OPS_FL_GRAPH,
+		      "function graph ops registered again"))
+		return -EBUSY;
+
 	guard(mutex)(&ftrace_lock);
 
 	if (!fgraph_stack_cachep) {
@@ -1401,17 +1405,21 @@ void unregister_ftrace_graph(struct fgraph_ops *gops)
 {
 	int command = 0;
 
+	if (WARN_ONCE(!(gops->ops.flags & FTRACE_OPS_FL_GRAPH),
+		      "function graph ops unregistered without registering"))
+		return;
+
 	guard(mutex)(&ftrace_lock);
 
 	if (unlikely(!ftrace_graph_active))
-		return;
+		goto out;
 
 	if (unlikely(gops->idx < 0 || gops->idx >= FGRAPH_ARRAY_SIZE ||
 		     fgraph_array[gops->idx] != gops))
-		return;
+		goto out;
 
 	if (fgraph_lru_release_index(gops->idx) < 0)
-		return;
+		goto out;
 
 	fgraph_array[gops->idx] = &fgraph_stub;
 
@@ -1434,4 +1442,6 @@ void unregister_ftrace_graph(struct fgraph_ops *gops)
 		unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
 	}
 	gops->saved_func = NULL;
+ out:
+	gops->ops.flags &= ~FTRACE_OPS_FL_GRAPH;
 }
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4203fad56b6c..00b76d450a89 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1042,10 +1042,6 @@ static struct ftrace_ops *removed_ops;
  */
 static bool update_all_ops;
 
-#ifndef CONFIG_FTRACE_MCOUNT_RECORD
-# error Dynamic ftrace depends on MCOUNT_RECORD
-#endif
-
 struct ftrace_func_probe {
 	struct ftrace_probe_ops	*probe_ops;
 	struct ftrace_ops	ops;
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 14d74a7491b8..66e1a527cf1a 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -513,7 +513,7 @@ static void print_graph_proc(struct trace_seq *s, pid_t pid)
 {
 	char comm[TASK_COMM_LEN];
 	/* sign + log10(MAX_INT) + '\0' */
-	char pid_str[11];
+	char pid_str[12];
 	int spaces = 0;
 	int len;
 	int i;