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-rw-r--r--kernel/posix-cpu-timers.c7
-rw-r--r--kernel/sched_stats.h15
2 files changed, 16 insertions, 6 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 153dcb2639c..895337b16a2 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -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;
diff --git a/kernel/sched_stats.h b/kernel/sched_stats.h
index ee71bec1da6..7dbf72a2b02 100644
--- a/kernel/sched_stats.h
+++ b/kernel/sched_stats.h
@@ -298,9 +298,11 @@ static inline void account_group_user_time(struct task_struct *tsk,
{
struct signal_struct *sig;
- sig = tsk->signal;
- if (unlikely(!sig))
+ /* tsk == current, ensure it is safe to use ->signal */
+ if (unlikely(tsk->exit_state))
return;
+
+ sig = tsk->signal;
if (sig->cputime.totals) {
struct task_cputime *times;
@@ -325,9 +327,11 @@ static inline void account_group_system_time(struct task_struct *tsk,
{
struct signal_struct *sig;
- sig = tsk->signal;
- if (unlikely(!sig))
+ /* tsk == current, ensure it is safe to use ->signal */
+ if (unlikely(tsk->exit_state))
return;
+
+ sig = tsk->signal;
if (sig->cputime.totals) {
struct task_cputime *times;
@@ -353,8 +357,11 @@ static inline void account_group_exec_runtime(struct task_struct *tsk,
struct signal_struct *sig;
sig = tsk->signal;
+ /* see __exit_signal()->task_rq_unlock_wait() */
+ barrier();
if (unlikely(!sig))
return;
+
if (sig->cputime.totals) {
struct task_cputime *times;