1 files changed, 6 insertions, 3 deletions

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 153dcb2639c3..4e5288a831de 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -311,7 +311,7 @@ static int cpu_clock_sample_group(const clockid_t which_clock,
         struct task_cputime cputime;
 
         thread_group_cputime(p, &cputime);
-        switch (which_clock) {
+        switch (CPUCLOCK_WHICH(which_clock)) {
         default:
                 return -EINVAL;
         case CPUCLOCK_PROF:
@@ -1308,9 +1308,10 @@ static inline int task_cputime_expired(const struct task_cputime *sample,
  */
 static inline int fastpath_timer_check(struct task_struct *tsk)
 {
-        struct signal_struct *sig = tsk->signal;
+        struct signal_struct *sig;
 
-        if (unlikely(!sig))
+        /* tsk == current, ensure it is safe to use ->signal/sighand */
+        if (unlikely(tsk->exit_state))
                 return 0;
 
         if (!task_cputime_zero(&tsk->cputime_expires)) {
@@ -1323,6 +1324,8 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
                 if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
                         return 1;
         }
+
+        sig = tsk->signal;
         if (!task_cputime_zero(&sig->cputime_expires)) {
                 struct task_cputime group_sample;