On Sat, Nov 30, 2024 at 7:20 AM Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> wrote: > > On 20/11/2024 22:17:34+0800, 高永良 wrote: > > Hi Alexandre Belloni, > > > > I've noticed that the post-failure process for __rtc_read_time requires > > careful handling. > > 1. Need to call pm_relax. > > I had a look when taking your patch and I'm not convinced calling > pm_relax is necessary. Before all the code of schedule_work(&rtc->irqwork), pm_stay_awake(rtc->dev.parent) is called. There are the following 4 functions: - rtc_set_time - rtc_update_irq - rtc_timer_enqueue - rtc_timer_remove At the end of the normal processing flow of the rtc_timer_do_work function, pm_relax(rtc->dev.parent) is called. So, if it fails here, pm_relax(rtc->dev.parent) should be called, right? > > > 2. Potentially need to set the alarm to ensure subsequent interrupts can > > process the > > expired timer? Could you give me some advice? > > Same thing, if you are not able to read the current time, setting the > next alarm is going to fail anyway. OK, I won't set the next alarm if it fails here. Thanks. > > > Should I continue to submit a fix patch or create a v2 version of the patch? > > > > Best Regards, > > Yongliang Gao > > > > Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> 于2024年11月12日周二 06:11写道： > > > > > On Fri, 11 Oct 2024 12:31:53 +0800, Yongliang Gao wrote: > > > > If the __rtc_read_time call fails,, the struct rtc_time tm; may contain > > > > uninitialized data, or an illegal date/time read from the RTC hardware. > > > > > > > > When calling rtc_tm_to_ktime later, the result may be a very large value > > > > (possibly KTIME_MAX). If there are periodic timers in rtc->timerqueue, > > > > they will continually expire, may causing kernel softlockup. > > > > > > > > [...] > > > > > > Applied, thanks! > > > > > > [1/1] rtc: check if __rtc_read_time was successful in rtc_timer_do_work() > > > https://git.kernel.org/abelloni/c/e8ba8a2bc4f6 > > > > > > Best regards, > > > > > > -- > > > Alexandre Belloni, co-owner and COO, Bootlin > > > Embedded Linux and Kernel engineering > > > https://bootlin.com > > > > > -- > Alexandre Belloni, co-owner and COO, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com
