Don't allow user-level helpers to be run when our infrastructure

isn't ready for it (either during early boot, or at shutdown)

init/main.c

@@ -82,6 +82,12 @@ extern void tc_init(void);
 extern void ipc_init(void);
 #endif
 
+/*
+ * Are we up and running (ie do we have all the infrastructure
+ * set up)
+ */
+int system_running = 0;
+
 /*
  * Boot command-line arguments
  */
@@ -559,6 +565,7 @@ static int init(void * unused)
 	 */
 	free_initmem();
 	unlock_kernel();
+	system_running = 1;
 
 	kstat.pgfree = 0;
 

kernel/kmod.c

@@ -32,7 +32,7 @@
 
 #include <asm/uaccess.h>
 
-extern int max_threads;
+extern int max_threads, system_running;
 
 static inline void
 use_init_fs_context(void)
@@ -158,6 +158,9 @@ static int exec_modprobe(void * module_name)
 	char *argv[] = { modprobe_path, "-s", "-k", "--", (char*)module_name, NULL };
 	int ret;
 
+	if (!system_running)
+		return -EBUSY;
+
 	ret = exec_usermodehelper(modprobe_path, argv, envp);
 	if (ret) {
 		static unsigned long last;
@@ -197,10 +200,9 @@ int request_module(const char * module_name)
 	unsigned long saved_policy = current->policy;
 
 	current->policy = SCHED_NORMAL;
-	/* Don't allow request_module() before the root fs is mounted!  */
-	if ( ! current->fs->root ) {
-		printk(KERN_ERR "request_module[%s]: Root fs not mounted\n",
-			module_name);
+	/* Don't allow request_module() when the system isn't set up */
+	if ( ! system_running ) {
+		printk(KERN_ERR "request_module[%s]: not ready\n", module_name);
 		ret = -EPERM;
 		goto out;
 	}
@@ -357,6 +359,9 @@ int call_usermodehelper(char *path, char **argv, char **envp)
 		.data		= &sub_info,
 	};
 
+	if (!system_running)
+		return -EBUSY;
+
 	if (path[0] == '\0')
 		goto out;
 

kernel/sys.c

@@ -323,6 +323,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void * arg)
 	switch (cmd) {
 	case LINUX_REBOOT_CMD_RESTART:
 		notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
+		system_running = 0;
 		device_shutdown();
 		printk(KERN_EMERG "Restarting system.\n");
 		machine_restart(NULL);
@@ -338,6 +339,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void * arg)
 
 	case LINUX_REBOOT_CMD_HALT:
 		notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
+		system_running = 0;
 		device_shutdown();
 		printk(KERN_EMERG "System halted.\n");
 		machine_halt();
@@ -346,6 +348,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void * arg)
 
 	case LINUX_REBOOT_CMD_POWER_OFF:
 		notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
+		system_running = 0;
 		device_shutdown();
 		printk(KERN_EMERG "Power down.\n");
 		machine_power_off();
@@ -360,6 +363,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void * arg)
 		buffer[sizeof(buffer) - 1] = '\0';
 
 		notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
+		system_running = 0;
 		device_shutdown();
 		printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
 		machine_restart(buffer);