/* * kernel/freezer.c - Function to freeze a process * * Originally from kernel/power/process.c */ #include #include #include #include #include #include /* total number of freezing conditions in effect */ atomic_t system_freezing_cnt = ATOMIC_INIT(0); EXPORT_SYMBOL(system_freezing_cnt); /* indicate whether PM freezing is in effect, protected by pm_mutex */ bool pm_freezing; bool pm_nosig_freezing; /* * Temporary export for the deadlock workaround in ata_scsi_hotplug(). * Remove once the hack becomes unnecessary. */ EXPORT_SYMBOL_GPL(pm_freezing); /* protects freezing and frozen transitions */ static DEFINE_SPINLOCK(freezer_lock); /** * freezing_slow_path - slow path for testing whether a task needs to be frozen * @p: task to be tested * * This function is called by freezing() if system_freezing_cnt isn't zero * and tests whether @p needs to enter and stay in frozen state. Can be * called under any context. The freezers are responsible for ensuring the * target tasks see the updated state. */ bool freezing_slow_path(struct task_struct *p) { if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK)) return false; if (test_tsk_thread_flag(p, TIF_MEMDIE)) return false; if (pm_nosig_freezing || cgroup_freezing(p)) return true; if (pm_freezing && !(p->flags & PF_KTHREAD)) return true; return false; } EXPORT_SYMBOL(freezing_slow_path); /* Refrigerator is place where frozen processes are stored :-). */ bool __refrigerator(bool check_kthr_stop) { /* Hmm, should we be allowed to suspend when there are realtime processes around? */ bool was_frozen = false; long save = current->state; pr_debug("%s entered refrigerator\n", current->comm); for (;;) { set_current_state(TASK_UNINTERRUPTIBLE); spin_lock_irq(&freezer_lock); current->flags |= PF_FROZEN; if (!freezing(current) || (check_kthr_stop && kthread_should_stop())) current->flags &= ~PF_FROZEN; spin_unlock_irq(&freezer_lock); if (!(current->flags & PF_FROZEN)) break; was_frozen = true; schedule(); } pr_debug("%s left refrigerator\n", current->comm); /* * Restore saved task state before returning. The mb'd version * needs to be used; otherwise, it might silently break * synchronization which depends on ordered task state change. */ set_current_state(save); return was_frozen; } EXPORT_SYMBOL(__refrigerator); static void fake_signal_wake_up(struct task_struct *p) { unsigned long flags; if (lock_task_sighand(p, &flags)) { signal_wake_up(p, 0); unlock_task_sighand(p, &flags); } } /** * freeze_task - send a freeze request to given task * @p: task to send the request to * * If @p is freezing, the freeze request is sent either by sending a fake * signal (if it's not a kernel thread) or waking it up (if it's a kernel * thread). * * RETURNS: * %false, if @p is not freezing or already frozen; %true, otherwise */ bool freeze_task(struct task_struct *p) { unsigned long flags; /* * This check can race with freezer_do_not_count, but worst case that * will result in an extra wakeup being sent to the task. It does not * race with freezer_count(), the barriers in freezer_count() and * freezer_should_skip() ensure that either freezer_count() sees * freezing == true in try_to_freeze() and freezes, or * freezer_should_skip() sees !PF_FREEZE_SKIP and freezes the task * normally. */ if (freezer_should_skip(p)) return false; spin_lock_irqsave(&freezer_lock, flags); if (!freezing(p) || frozen(p)) { spin_unlock_irqrestore(&freezer_lock, flags); return false; } if (!(p->flags & PF_KTHREAD)) fake_signal_wake_up(p); else wake_up_state(p, TASK_INTERRUPTIBLE); spin_unlock_irqrestore(&freezer_lock, flags); return true; } void __thaw_task(struct task_struct *p) { unsigned long flags; spin_lock_irqsave(&freezer_lock, flags); if (frozen(p)) wake_up_process(p); spin_unlock_irqrestore(&freezer_lock, flags); } /** * set_freezable - make %current freezable * * Mark %current freezable and enter refrigerator if necessary. */ bool set_freezable(void) { might_sleep(); /* * Modify flags while holding freezer_lock. This ensures the * freezer notices that we aren't frozen yet or the freezing * condition is visible to try_to_freeze() below. */ spin_lock_irq(&freezer_lock); current->flags &= ~PF_NOFREEZE; spin_unlock_irq(&freezer_lock); return try_to_freeze(); } EXPORT_SYMBOL(set_freezable); option>space:mode:
authorThomas Gleixner <tglx@linutronix.de>2017-01-31 09:37:34 +0100
committerThomas Gleixner <tglx@linutronix.de>2017-01-31 21:47:58 +0100
commit0becc0ae5b42828785b589f686725ff5bc3b9b25 (patch)
treebe6d0e1f37c38ed0a7dd5da2d4b1e93f0fb43101 /include/dt-bindings/pinctrl/rockchip.h
parent24c2503255d35c269b67162c397a1a1c1e02f6ce (diff)
x86/mce: Make timer handling more robust
Erik reported that on a preproduction hardware a CMCI storm triggers the BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is started by the CMCI logic before the MCE CPU hotplug callback starts the timer with add_timer_on(). So the timer is already queued which triggers the BUG. Using add_timer_on() is pretty pointless in this code because the timer is strictlty per CPU, initialized as pinned and all operations which arm the timer happen on the CPU to which the timer belongs. Simplify the whole machinery by using mod_timer() instead of add_timer_on() which avoids the problem because mod_timer() can handle already queued timers. Use __start_timer() everywhere so the earliest armed expiry time is preserved. Reported-by: Erik Veijola <erik.veijola@intel.com> Tested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@alien8.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/dt-bindings/pinctrl/rockchip.h')