Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/linville...

[pandora-kernel.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index b77fd55..26a7a67 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -66,6 +66,7 @@
 #include <linux/user-return-notifier.h>
 #include <linux/oom.h>
 #include <linux/khugepaged.h>
+#include <linux/signalfd.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -667,6 +668,38 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
        return mm;
 }
 
+static void complete_vfork_done(struct task_struct *tsk)
+{
+       struct completion *vfork;
+
+       task_lock(tsk);
+       vfork = tsk->vfork_done;
+       if (likely(vfork)) {
+               tsk->vfork_done = NULL;
+               complete(vfork);
+       }
+       task_unlock(tsk);
+}
+
+static int wait_for_vfork_done(struct task_struct *child,
+                               struct completion *vfork)
+{
+       int killed;
+
+       freezer_do_not_count();
+       killed = wait_for_completion_killable(vfork);
+       freezer_count();
+
+       if (killed) {
+               task_lock(child);
+               child->vfork_done = NULL;
+               task_unlock(child);
+       }
+
+       put_task_struct(child);
+       return killed;
+}
+
 /* Please note the differences between mmput and mm_release.
  * mmput is called whenever we stop holding onto a mm_struct,
  * error success whatever.
@@ -682,8 +715,6 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
  */
 void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 {
-       struct completion *vfork_done = tsk->vfork_done;
-
        /* Get rid of any futexes when releasing the mm */
 #ifdef CONFIG_FUTEX
        if (unlikely(tsk->robust_list)) {
@@ -703,17 +734,15 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
        /* Get rid of any cached register state */
        deactivate_mm(tsk, mm);
 
-       /* notify parent sleeping on vfork() */
-       if (vfork_done) {
-               tsk->vfork_done = NULL;
-               complete(vfork_done);
-       }
+       if (tsk->vfork_done)
+               complete_vfork_done(tsk);
 
        /*
         * If we're exiting normally, clear a user-space tid field if
         * requested.  We leave this alone when dying by signal, to leave
         * the value intact in a core dump, and to save the unnecessary
-        * trouble otherwise.  Userland only wants this done for a sys_exit.
+        * trouble, say, a killed vfork parent shouldn't touch this mm.
+        * Userland only wants this done for a sys_exit.
         */
        if (tsk->clear_child_tid) {
                if (!(tsk->flags & PF_SIGNALED) &&
@@ -935,8 +964,10 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
 
 void __cleanup_sighand(struct sighand_struct *sighand)
 {
-       if (atomic_dec_and_test(&sighand->count))
+       if (atomic_dec_and_test(&sighand->count)) {
+               signalfd_cleanup(sighand);
                kmem_cache_free(sighand_cachep, sighand);
+       }
 }
 
 
@@ -1015,7 +1046,6 @@ static void copy_flags(unsigned long clone_flags, struct task_struct *p)
 
        new_flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER);
        new_flags |= PF_FORKNOEXEC;
-       new_flags |= PF_STARTING;
        p->flags = new_flags;
 }
 
@@ -1545,16 +1575,9 @@ long do_fork(unsigned long clone_flags,
                if (clone_flags & CLONE_VFORK) {
                        p->vfork_done = &vfork;
                        init_completion(&vfork);
+                       get_task_struct(p);
                }
 
-               /*
-                * We set PF_STARTING at creation in case tracing wants to
-                * use this to distinguish a fully live task from one that
-                * hasn't finished SIGSTOP raising yet.  Now we clear it
-                * and set the child going.
-                */
-               p->flags &= ~PF_STARTING;
-
                wake_up_new_task(p);
 
                /* forking complete and child started to run, tell ptracer */
@@ -1562,10 +1585,8 @@ long do_fork(unsigned long clone_flags,
                        ptrace_event(trace, nr);
 
                if (clone_flags & CLONE_VFORK) {
-                       freezer_do_not_count();
-                       wait_for_completion(&vfork);
-                       freezer_count();
-                       ptrace_event(PTRACE_EVENT_VFORK_DONE, nr);
+                       if (!wait_for_vfork_done(p, &vfork))
+                               ptrace_event(PTRACE_EVENT_VFORK_DONE, nr);
                }
        } else {
                nr = PTR_ERR(p);