timers: fix itimer/many thread hang, fix

fix bogus rq dereference: v3 removed the locking but also removed the rq
initialization.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 1 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 29a3152c45db..ebb03def564b 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4042,10 +4042,12 @@ EXPORT_PER_CPU_SYMBOL(kstat);
  */
 unsigned long long task_delta_exec(struct task_struct *p)
 {
-        struct rq *rq;
         unsigned long flags;
+        struct rq *rq;
         u64 ns = 0;
 
+        rq = task_rq_lock(p, &flags);
+
         if (task_current(rq, p)) {
                 u64 delta_exec;
 
@@ -4055,6 +4057,8 @@ unsigned long long task_delta_exec(struct task_struct *p)
                         ns = delta_exec;
         }
 
+        task_rq_unlock(rq, &flags);
+
         return ns;
 }