pstore/ftrace: Keep ftrace module parameter and debugfs switch in sync

Commit a5d05b0 ("pstore/ftrace: Allow immediate recording")
introduced a kernel parameter to enable early-boot collection for
ftrace frontend. But then, if we enable the debugfs later, the
parameter remains set as N. This is not a biggie, things work fine;
but at the same time, why not have both in sync if possible, right?

Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Link: https://patch.msgid.link/20260301192704.1263589-1-gpiccoli@igalia.com
Signed-off-by: Kees Cook <kees@kernel.org>

Author: guilhermepiccoli

fs/pstore/ftrace.c

@@ -62,13 +62,16 @@ static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
 };
 
 static DEFINE_MUTEX(pstore_ftrace_lock);
-static bool pstore_ftrace_enabled;
+static bool record_ftrace;
+module_param(record_ftrace, bool, 0400);
+MODULE_PARM_DESC(record_ftrace,
+		 "enable ftrace recording immediately (default: off)");
 
 static int pstore_set_ftrace_enabled(bool on)
 {
 	ssize_t ret;
 
-	if (on == pstore_ftrace_enabled)
+	if (on == record_ftrace)
 		return 0;
 
 	if (on) {
@@ -82,7 +85,7 @@ static int pstore_set_ftrace_enabled(bool on)
 		pr_err("%s: unable to %sregister ftrace ops: %zd\n",
 		       __func__, on ? "" : "un", ret);
 	} else {
-		pstore_ftrace_enabled = on;
+		record_ftrace = on;
 	}
 
 	return ret;
@@ -111,7 +114,7 @@ static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
 static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
 				       size_t count, loff_t *ppos)
 {
-	char val[] = { '0' + pstore_ftrace_enabled, '\n' };
+	char val[] = { '0' + record_ftrace, '\n' };
 
 	return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
 }
@@ -124,11 +127,6 @@ static const struct file_operations pstore_knob_fops = {
 
 static struct dentry *pstore_ftrace_dir;
 
-static bool record_ftrace;
-module_param(record_ftrace, bool, 0400);
-MODULE_PARM_DESC(record_ftrace,
-		 "enable ftrace recording immediately (default: off)");
-
 void pstore_register_ftrace(void)
 {
 	if (!psinfo->write)
@@ -145,9 +143,9 @@ void pstore_register_ftrace(void)
 void pstore_unregister_ftrace(void)
 {
 	mutex_lock(&pstore_ftrace_lock);
-	if (pstore_ftrace_enabled) {
+	if (record_ftrace) {
 		unregister_ftrace_function(&pstore_ftrace_ops);
-		pstore_ftrace_enabled = false;
+		record_ftrace = false;
 	}
 	mutex_unlock(&pstore_ftrace_lock);