1 files changed, 14 insertions, 5 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 546774a31a66..cce59cb5ee6a 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -85,7 +85,9 @@ static void __exit_signal(struct task_struct *tsk)
         BUG_ON(!sig);
         BUG_ON(!atomic_read(&sig->count));
 
-        sighand = rcu_dereference(tsk->sighand);
+        sighand = rcu_dereference_check(tsk->sighand,
+                                        rcu_read_lock_held() ||
+                                        lockdep_tasklist_lock_is_held());
         spin_lock(&sighand->siglock);
 
         posix_cpu_timers_exit(tsk);
@@ -170,8 +172,10 @@ void release_task(struct task_struct * p)
 repeat:
         tracehook_prepare_release_task(p);
         /* don't need to get the RCU readlock here - the process is dead and
-         * can't be modifying its own credentials */
+         * can't be modifying its own credentials. But shut RCU-lockdep up */
+        rcu_read_lock();
         atomic_dec(&__task_cred(p)->user->processes);
+        rcu_read_unlock();
 
         proc_flush_task(p);
 
@@ -473,9 +477,11 @@ static void close_files(struct files_struct * files)
         /*
          * It is safe to dereference the fd table without RCU or
          * ->file_lock because this is the last reference to the
-         * files structure.
+         * files structure.  But use RCU to shut RCU-lockdep up.
          */
+        rcu_read_lock();
         fdt = files_fdtable(files);
+        rcu_read_unlock();
         for (;;) {
                 unsigned long set;
                 i = j * __NFDBITS;
@@ -521,10 +527,12 @@ void put_files_struct(struct files_struct *files)
                  * at the end of the RCU grace period. Otherwise,
                  * you can free files immediately.
                  */
+                rcu_read_lock();
                 fdt = files_fdtable(files);
                 if (fdt != &files->fdtab)
                         kmem_cache_free(files_cachep, files);
                 free_fdtable(fdt);
+                rcu_read_unlock();
         }
 }
 
@@ -944,7 +952,8 @@ NORET_TYPE void do_exit(long code)
                                 preempt_count());
 
         acct_update_integrals(tsk);
-
+        /* sync mm's RSS info before statistics gathering */
+        sync_mm_rss(tsk, tsk->mm);
         group_dead = atomic_dec_and_test(&tsk->signal->live);
         if (group_dead) {
                 hrtimer_cancel(&tsk->signal->real_timer);
@@ -1180,7 +1189,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 
         if (unlikely(wo->wo_flags & WNOWAIT)) {
                 int exit_code = p->exit_code;
-                int why, status;
+                int why;
 
                 get_task_struct(p);
                 read_unlock(&tasklist_lock);