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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 25 insertions, 19 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index b04ae0390df3..241507f23eca 100644
--- 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();
         }