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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0184-hrtimer-cpu_chill-save-task-state-in-saved_state.patch | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/debian/patches-rt/0184-hrtimer-cpu_chill-save-task-state-in-saved_state.patch b/debian/patches-rt/0184-hrtimer-cpu_chill-save-task-state-in-saved_state.patch new file mode 100644 index 000000000..6917a5783 --- /dev/null +++ b/debian/patches-rt/0184-hrtimer-cpu_chill-save-task-state-in-saved_state.patch @@ -0,0 +1,63 @@ +From 351c688963d6bfafec5cf05168e195effc77811c Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Tue, 26 Feb 2019 12:31:10 +0100 +Subject: [PATCH 184/347] hrtimer: cpu_chill(): save task state in + ->saved_state() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +In the previous change I saved the current task state on stack. This was +bad because while the task is scheduled-out it might receive a wake-up. +The wake up changes the task state and we must not destroy it. + +Save the task-state in ->saved_state under a PI-lock to unsure that +state changes during are not missed while the task temporary scheduled +out. + +Reported-by: Mike Galbraith <efault@gmx.de> +Tested-by: Mike Galbraith <efault@gmx.de> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + kernel/time/hrtimer.c | 18 +++++++++++++----- + 1 file changed, 13 insertions(+), 5 deletions(-) + +diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c +index 96e505abf939..aa8f3177580a 100644 +--- a/kernel/time/hrtimer.c ++++ b/kernel/time/hrtimer.c +@@ -1967,20 +1967,28 @@ COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp, + */ + void cpu_chill(void) + { +- ktime_t chill_time; + unsigned int freeze_flag = current->flags & PF_NOFREEZE; +- long saved_state; ++ struct task_struct *self = current; ++ ktime_t chill_time; + +- saved_state = current->state; +- chill_time = ktime_set(0, NSEC_PER_MSEC); ++ raw_spin_lock_irq(&self->pi_lock); ++ self->saved_state = self->state; + __set_current_state_no_track(TASK_UNINTERRUPTIBLE); ++ raw_spin_unlock_irq(&self->pi_lock); ++ ++ chill_time = ktime_set(0, NSEC_PER_MSEC); ++ + 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); ++ ++ raw_spin_lock_irq(&self->pi_lock); ++ __set_current_state_no_track(self->saved_state); ++ self->saved_state = TASK_RUNNING; ++ raw_spin_unlock_irq(&self->pi_lock); + } + EXPORT_SYMBOL(cpu_chill); + #endif +-- +2.36.1 + |