5 files changed, 40 insertions, 7 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 8185a0f09594..2606d0fb4e54 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1024,7 +1024,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
                 if (ret == -EBUSY) {
                         mutex_unlock(&cgroup_mutex);
                         mutex_unlock(&inode->i_mutex);
-                        goto drop_new_super;
+                        goto free_cg_links;
                 }
 
                 /* EBUSY should be the only error here */
@@ -1073,10 +1073,11 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
 
         return simple_set_mnt(mnt, sb);
 
+ free_cg_links:
+        free_cg_links(&tmp_cg_links);
  drop_new_super:
         up_write(&sb->s_umount);
         deactivate_super(sb);
-        free_cg_links(&tmp_cg_links);
         return ret;
 }
 
@@ -2934,9 +2935,6 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
  again:
         root = subsys->root;
         if (root == &rootnode) {
-                printk(KERN_INFO
-                       "Not cloning cgroup for unused subsystem %s\n",
-                       subsys->name);
                 mutex_unlock(&cgroup_mutex);
                 return 0;
         }
diff --git a/kernel/fork.c b/kernel/fork.c
index 7b93da72d4a2..65ce60adc8e8 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1096,6 +1096,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 #ifdef CONFIG_DEBUG_MUTEXES
         p->blocked_on = NULL; /* not blocked yet */
 #endif
+        if (unlikely(ptrace_reparented(current)))
+                ptrace_fork(p, clone_flags);
 
         /* Perform scheduler related setup. Assign this task to a CPU. */
         sched_fork(p, clone_flags);
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 5e79c662294b..a140e44eebba 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -197,6 +197,11 @@ static int common_timer_create(struct k_itimer *new_timer)
         return 0;
 }
 
+static int no_timer_create(struct k_itimer *new_timer)
+{
+        return -EOPNOTSUPP;
+}
+
 /*
  * Return nonzero if we know a priori this clockid_t value is bogus.
  */
@@ -248,6 +253,7 @@ static __init int init_posix_timers(void)
                 .clock_getres = hrtimer_get_res,
                 .clock_get = posix_get_monotonic_raw,
                 .clock_set = do_posix_clock_nosettime,
+                .timer_create = no_timer_create,
         };
 
         register_posix_clock(CLOCK_REALTIME, &clock_realtime);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 4c8bcd7dd8e0..100a71cfdaba 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -25,6 +25,17 @@
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
 
+
+/*
+ * Initialize a new task whose father had been ptraced.
+ *
+ * Called from copy_process().
+ */
+void ptrace_fork(struct task_struct *child, unsigned long clone_flags)
+{
+        arch_ptrace_fork(child, clone_flags);
+}
+
 /*
  * ptrace a task: make the debugger its new parent and
  * move it to the ptrace list.
@@ -72,6 +83,7 @@ void __ptrace_unlink(struct task_struct *child)
         child->parent = child->real_parent;
         list_del_init(&child->ptrace_entry);
 
+        arch_ptrace_untrace(child);
         if (task_is_traced(child))
                 ptrace_untrace(child);
 }
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index bb6922a931b1..76f34c0ef29c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -838,6 +838,7 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
          * back to us). This allows us to do a simple loop to
          * assign the commit to the tail.
          */
+ again:
         while (cpu_buffer->commit_page != cpu_buffer->tail_page) {
                 cpu_buffer->commit_page->page->commit =
                         cpu_buffer->commit_page->write;
@@ -853,6 +854,17 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
                         cpu_buffer->commit_page->write;
                 barrier();
         }
+
+        /* again, keep gcc from optimizing */
+        barrier();
+
+        /*
+         * If an interrupt came in just after the first while loop
+         * and pushed the tail page forward, we will be left with
+         * a dangling commit that will never go forward.
+         */
+        if (unlikely(cpu_buffer->commit_page != cpu_buffer->tail_page))
+                goto again;
 }
 
 static void rb_reset_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
@@ -950,12 +962,15 @@ static struct ring_buffer_event *
 __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
                   unsigned type, unsigned long length, u64 *ts)
 {
-        struct buffer_page *tail_page, *head_page, *reader_page;
+        struct buffer_page *tail_page, *head_page, *reader_page, *commit_page;
         unsigned long tail, write;
         struct ring_buffer *buffer = cpu_buffer->buffer;
         struct ring_buffer_event *event;
         unsigned long flags;
 
+        commit_page = cpu_buffer->commit_page;
+        /* we just need to protect against interrupts */
+        barrier();
         tail_page = cpu_buffer->tail_page;
         write = local_add_return(length, &tail_page->write);
         tail = write - length;
@@ -981,7 +996,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
                  * it all the way around the buffer, bail, and warn
                  * about it.
                  */
-                if (unlikely(next_page == cpu_buffer->commit_page)) {
+                if (unlikely(next_page == commit_page)) {
                         WARN_ON_ONCE(1);
                         goto out_unlock;
                 }