kernel/sys.c: avoid argv_free(NULL)

If argv_split() failed, the code will end up calling argv_free(NULL).  Fix
it up and clean things up a bit.

Addresses Coverity report 703573.

Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/sys.c b/kernel/sys.c
index b04ae0390df35833613b5b3afb7b19c826ae6c94..241507f23eca097871bec58f5976476f352f3d75 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2186,46 +2186,52 @@ static void argv_cleanup(struct subprocess_info *info)
        argv_free(info->argv);
 }
 
-/**
- * orderly_poweroff - Trigger an orderly system poweroff
- * @force: force poweroff if command execution fails
- *
- * This may be called from any context to trigger a system shutdown.
- * If the orderly shutdown fails, it will force an immediate shutdown.
- */
-int orderly_poweroff(bool force)
+static int __orderly_poweroff(void)
 {
        int argc;
-       char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
+       char **argv;
        static char *envp[] = {
                "HOME=/",
                "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
                NULL
        };
-       int ret = -ENOMEM;
+       int ret;
 
+       argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
        if (argv == NULL) {
                printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
                       __func__, poweroff_cmd);
-               goto out;
+               return -ENOMEM;
        }
 
        ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_NO_WAIT,
                                      NULL, argv_cleanup, NULL);
-out:
-       if (likely(!ret))
-               return 0;
-
        if (ret == -ENOMEM)
                argv_free(argv);
 
-       if (force) {
+       return ret;
+}
+
+/**
+ * orderly_poweroff - Trigger an orderly system poweroff
+ * @force: force poweroff if command execution fails
+ *
+ * This may be called from any context to trigger a system shutdown.
+ * If the orderly shutdown fails, it will force an immediate shutdown.
+ */
+int orderly_poweroff(bool force)
+{
+       int ret = __orderly_poweroff();
+
+       if (ret && force) {
                printk(KERN_WARNING "Failed to start orderly shutdown: "
                       "forcing the issue\n");
 
-               /* I guess this should try to kick off some daemon to
-                  sync and poweroff asap.  Or not even bother syncing
-                  if we're doing an emergency shutdown? */
+               /*
+                * I guess this should try to kick off some daemon to sync and
+                * poweroff asap.  Or not even bother syncing if we're doing an
+                * emergency shutdown?
+                */
                emergency_sync();
                kernel_power_off();
        }