1 files changed, 30 insertions, 14 deletions

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 3a7379aa31ca..796276141e51 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -217,7 +217,10 @@ static int wait_for_helper(void *data)
                         sub_info->retval = ret;
         }
 
-        complete(sub_info->complete);
+        if (sub_info->wait < 0)
+                kfree(sub_info);
+        else
+                complete(sub_info->complete);
         return 0;
 }
 
@@ -239,6 +242,9 @@ static void __call_usermodehelper(struct work_struct *work)
                 pid = kernel_thread(____call_usermodehelper, sub_info,
                                     CLONE_VFORK | SIGCHLD);
 
+        if (wait < 0)
+                return;
+
         if (pid < 0) {
                 sub_info->retval = pid;
                 complete(sub_info->complete);
@@ -253,6 +259,9 @@ static void __call_usermodehelper(struct work_struct *work)
  * @envp: null-terminated environment list
  * @session_keyring: session keyring for process (NULL for an empty keyring)
  * @wait: wait for the application to finish and return status.
+ *        when -1 don't wait at all, but you get no useful error back when
+ *        the program couldn't be exec'ed. This makes it safe to call
+ *        from interrupt context.
  *
  * Runs a user-space application.  The application is started
  * asynchronously if wait is not set, and runs as a child of keventd.
@@ -265,17 +274,8 @@ int call_usermodehelper_keys(char *path, char **argv, char **envp,
                              struct key *session_keyring, int wait)
 {
         DECLARE_COMPLETION_ONSTACK(done);
-        struct subprocess_info sub_info = {
-                .work           = __WORK_INITIALIZER(sub_info.work,
-                                                     __call_usermodehelper),
-                .complete       = &done,
-                .path           = path,
-                .argv           = argv,
-                .envp           = envp,
-                .ring           = session_keyring,
-                .wait           = wait,
-                .retval         = 0,
-        };
+        struct subprocess_info *sub_info;
+        int retval;
 
         if (!khelper_wq)
                 return -EBUSY;
@@ -283,9 +283,25 @@ int call_usermodehelper_keys(char *path, char **argv, char **envp,
         if (path[0] == '\0')
                 return 0;
 
-        queue_work(khelper_wq, &sub_info.work);
+        sub_info = kzalloc(sizeof(struct subprocess_info),  GFP_ATOMIC);
+        if (!sub_info)
+                return -ENOMEM;
+
+        INIT_WORK(&sub_info->work, __call_usermodehelper);
+        sub_info->complete = &done;
+        sub_info->path = path;
+        sub_info->argv = argv;
+        sub_info->envp = envp;
+        sub_info->ring = session_keyring;
+        sub_info->wait = wait;
+
+        queue_work(khelper_wq, &sub_info->work);
+        if (wait < 0) /* task has freed sub_info */
+                return 0;
         wait_for_completion(&done);
-        return sub_info.retval;
+        retval = sub_info->retval;
+        kfree(sub_info);
+        return retval;
 }
 EXPORT_SYMBOL(call_usermodehelper_keys);