1 files changed, 15 insertions, 5 deletions

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 20a997c73c3d..842f8015d7fd 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -20,7 +20,6 @@
 */
 #define __KERNEL_SYSCALLS__
 
-#include <linux/config.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/syscalls.h>
@@ -177,6 +176,8 @@ static int wait_for_helper(void *data)
         if (pid < 0) {
                 sub_info->retval = pid;
         } else {
+                int ret;
+
                 /*
                  * Normally it is bogus to call wait4() from in-kernel because
                  * wait4() wants to write the exit code to a userspace address.
@@ -186,7 +187,15 @@ static int wait_for_helper(void *data)
                  *
                  * Thus the __user pointer cast is valid here.
                  */
-                sys_wait4(pid, (int __user *) &sub_info->retval, 0, NULL);
+                sys_wait4(pid, (int __user *)&ret, 0, NULL);
+
+                /*
+                 * If ret is 0, either ____call_usermodehelper failed and the
+                 * real error code is already in sub_info->retval or
+                 * sub_info->retval is 0 anyway, so don't mess with it then.
+                 */
+                if (ret)
+                        sub_info->retval = ret;
         }
 
         complete(sub_info->complete);
@@ -198,11 +207,12 @@ static void __call_usermodehelper(void *data)
 {
         struct subprocess_info *sub_info = data;
         pid_t pid;
+        int wait = sub_info->wait;
 
         /* CLONE_VFORK: wait until the usermode helper has execve'd
          * successfully We need the data structures to stay around
          * until that is done.  */
-        if (sub_info->wait)
+        if (wait)
                 pid = kernel_thread(wait_for_helper, sub_info,
                                     CLONE_FS | CLONE_FILES | SIGCHLD);
         else
@@ -212,7 +222,7 @@ static void __call_usermodehelper(void *data)
         if (pid < 0) {
                 sub_info->retval = pid;
                 complete(sub_info->complete);
-        } else if (!sub_info->wait)
+        } else if (!wait)
                 complete(sub_info->complete);
 }
 
@@ -234,7 +244,7 @@ static void __call_usermodehelper(void *data)
 int call_usermodehelper_keys(char *path, char **argv, char **envp,
                              struct key *session_keyring, int wait)
 {
-        DECLARE_COMPLETION(done);
+        DECLARE_COMPLETION_ONSTACK(done);
         struct subprocess_info sub_info = {
                 .complete       = &done,
                 .path           = path,