From: Sebastian Andrzej Siewior Date: Tue, 19 Feb 2019 16:59:15 +0100 Subject: [PATCH 183/353] hrtimer: Don't lose state in cpu_chill() Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=721ff03f231a027cb0e48525bec4e1ecc07f0c86 In cpu_chill() the state is set to TASK_UNINTERRUPTIBLE and a timer is programmed. On return the state is always TASK_RUNNING which means we lose the state if it was something other than RUNNING. Also set_current_state() sets ->task_state_change to within cpu_chill() which is not expected. Save the task state on entry and restore it on return. Simply set the state in order to avoid updating ->task_state_change. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior --- kernel/time/hrtimer.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 768de46dba6b..aa208a350a3b 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1971,15 +1971,18 @@ void cpu_chill(void) { ktime_t chill_time; unsigned int freeze_flag = current->flags & PF_NOFREEZE; + long saved_state; + saved_state = current->state; chill_time = ktime_set(0, NSEC_PER_MSEC); - set_current_state(TASK_UNINTERRUPTIBLE); + __set_current_state_no_track(TASK_UNINTERRUPTIBLE); current->flags |= PF_NOFREEZE; sleeping_lock_inc(); schedule_hrtimeout(&chill_time, HRTIMER_MODE_REL_HARD); sleeping_lock_dec(); if (!freeze_flag) current->flags &= ~PF_NOFREEZE; + __set_current_state_no_track(saved_state); } EXPORT_SYMBOL(cpu_chill); #endif