Merge branch 'master' into test

[tomoyo/tomoyo-test1.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 5c372c9..be8aa5b 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -606,6 +606,11 @@ static void __mmdrop(struct mm_struct *mm)
 
 void mmdrop(struct mm_struct *mm)
 {
+       /*
+        * The implicit full barrier implied by atomic_dec_and_test() is
+        * required by the membarrier system call before returning to
+        * user-space, after storing to rq->curr.
+        */
        if (unlikely(atomic_dec_and_test(&mm->mm_count)))
                __mmdrop(mm);
 }
@@ -1587,6 +1592,10 @@ static __latent_entropy struct task_struct *copy_process(
        int retval;
        struct task_struct *p;
 
+       /*
+        * Don't allow sharing the root directory with processes in a different
+        * namespace
+        */
        if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
                return ERR_PTR(-EINVAL);
 
@@ -2062,6 +2071,8 @@ long _do_fork(unsigned long clone_flags,
              int __user *child_tidptr,
              unsigned long tls)
 {
+       struct completion vfork;
+       struct pid *pid;
        struct task_struct *p;
        int trace = 0;
        long nr;
@@ -2087,43 +2098,40 @@ long _do_fork(unsigned long clone_flags,
        p = copy_process(clone_flags, stack_start, stack_size,
                         child_tidptr, NULL, trace, tls, NUMA_NO_NODE);
        add_latent_entropy();
+
+       if (IS_ERR(p))
+               return PTR_ERR(p);
+
        /*
         * Do this prior waking up the new thread - the thread pointer
         * might get invalid after that point, if the thread exits quickly.
         */
-       if (!IS_ERR(p)) {
-               struct completion vfork;
-               struct pid *pid;
-
-               trace_sched_process_fork(current, p);
+       trace_sched_process_fork(current, p);
 
-               pid = get_task_pid(p, PIDTYPE_PID);
-               nr = pid_vnr(pid);
+       pid = get_task_pid(p, PIDTYPE_PID);
+       nr = pid_vnr(pid);
 
-               if (clone_flags & CLONE_PARENT_SETTID)
-                       put_user(nr, parent_tidptr);
+       if (clone_flags & CLONE_PARENT_SETTID)
+               put_user(nr, parent_tidptr);
 
-               if (clone_flags & CLONE_VFORK) {
-                       p->vfork_done = &vfork;
-                       init_completion(&vfork);
-                       get_task_struct(p);
-               }
-
-               wake_up_new_task(p);
+       if (clone_flags & CLONE_VFORK) {
+               p->vfork_done = &vfork;
+               init_completion(&vfork);
+               get_task_struct(p);
+       }
 
-               /* forking complete and child started to run, tell ptracer */
-               if (unlikely(trace))
-                       ptrace_event_pid(trace, pid);
+       wake_up_new_task(p);
 
-               if (clone_flags & CLONE_VFORK) {
-                       if (!wait_for_vfork_done(p, &vfork))
-                               ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid);
-               }
+       /* forking complete and child started to run, tell ptracer */
+       if (unlikely(trace))
+               ptrace_event_pid(trace, pid);
 
-               put_pid(pid);
-       } else {
-               nr = PTR_ERR(p);
+       if (clone_flags & CLONE_VFORK) {
+               if (!wait_for_vfork_done(p, &vfork))
+                       ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid);
        }
+
+       put_pid(pid);
        return nr;
 }