diff --git a/sys/compat/linuxkpi/common/include/linux/moduleparam.h b/sys/compat/linuxkpi/common/include/linux/moduleparam.h
--- a/sys/compat/linuxkpi/common/include/linux/moduleparam.h
+++ b/sys/compat/linuxkpi/common/include/linux/moduleparam.h
@@ -53,6 +53,7 @@
 #define	LINUXKPI_PARAM_PASS(...) __VA_ARGS__
 #define	LINUXKPI_PARAM_DESC(name) LINUXKPI_PARAM_CONCAT(linuxkpi_,LINUXKPI_PARAM_PREFIX,name,_desc)
 #define	LINUXKPI_PARAM_NAME(name) LINUXKPI_PARAM_CONCAT(LINUXKPI_PARAM_PREFIX,name,,)
+#define	LINUXKPI_PARAM_UNINIT(name) LINUXKPI_PARAM_CONCAT(linuxkpi_,LINUXKPI_PARAM_PREFIX,name,_uninit)
 
 #define	LINUXKPI_PARAM_bool(name, var, perm)				\
 	extern const char LINUXKPI_PARAM_DESC(name)[];			\
@@ -104,9 +105,13 @@
 
 #define	LINUXKPI_PARAM_charp(name, var, perm)				\
 	extern const char LINUXKPI_PARAM_DESC(name)[];			\
-	LINUXKPI_PARAM_PASS(SYSCTL_STRING(LINUXKPI_PARAM_PARENT, OID_AUTO, \
-	LINUXKPI_PARAM_NAME(name), LINUXKPI_PARAM_PERM(perm), &(var), 0, \
-	LINUXKPI_PARAM_DESC(name)))
+	static void LINUXKPI_PARAM_UNINIT(name)(void *data) { kfree(LINUXKPI_PARAM_DESC(name)); } \
+	SYSUNINIT(LINUXKPI_PARAM_UNINIT(name), SI_SUB_KLD, SI_ORDER_MIDDLE, \
+	LINUXKPI_PARAM_UNINIT(name), NULL);			\
+	LINUXKPI_PARAM_PASS(SYSCTL_PROC(LINUXKPI_PARAM_PARENT, OID_AUTO, \
+	LINUXKPI_PARAM_NAME(name), \
+	LINUXKPI_PARAM_PERM(perm) | CTLTYPE_STRING | CTLFLAG_MPSAFE, \
+	&(var), 0, lkpi_sysctl_handle_charp, "A", LINUXKPI_PARAM_DESC(name)))
 
 #define	module_param_string(name, str, len, perm)			\
 	extern const char LINUXKPI_PARAM_DESC(name)[];			\
@@ -136,4 +141,6 @@
 
 SYSCTL_DECL(_compat_linuxkpi);
 
+extern int lkpi_sysctl_handle_charp(SYSCTL_HANDLER_ARGS);
+
 #endif					/* _LINUXKPI_LINUX_MODULEPARAM_H_ */
diff --git a/sys/compat/linuxkpi/common/src/linux_compat.c b/sys/compat/linuxkpi/common/src/linux_compat.c
--- a/sys/compat/linuxkpi/common/src/linux_compat.c
+++ b/sys/compat/linuxkpi/common/src/linux_compat.c
@@ -2728,6 +2728,47 @@
 	return (io_mapping_init_wc(mapping, base, size));
 }
 
+static struct sx lkpi_charp_lock;
+SX_SYSINIT(lkpi_charp, &lkpi_charp_lock, "lkpi charp module param lock");
+
+int
+lkpi_sysctl_handle_charp(SYSCTL_HANDLER_ARGS)
+{
+	char **charp = arg1;
+	int error = 0;
+
+	sx_xlock(&lkpi_charp_lock);
+
+	if (req->oldptr != NULL) {
+		error = SYSCTL_OUT_STR(req, *charp == NULL ? "" : *charp);
+	} else {
+		error = SYSCTL_OUT(req, NULL, *charp == NULL ? 1 : strlen(*charp) + 1);
+	}
+	if (error || !req->newptr) {
+		goto end;
+	}
+
+	kfree(*charp);
+
+	if (req->newlen == 0) {
+		*charp = NULL;
+		goto end;
+	}
+
+	*charp = kzalloc(req->newlen + 1, GFP_KERNEL);
+	error = SYSCTL_IN(req, *charp, req->newlen);
+	if (error) {
+		kfree(*charp);
+		*charp = NULL;
+	} else {
+		(*charp)[req->newlen] = '\0';
+	}
+
+end:
+	sx_xunlock(&lkpi_charp_lock);
+	return (error);
+}
+
 #if defined(__i386__) || defined(__amd64__)
 bool linux_cpu_has_clflush;
 #endif