On Saturday 27 October 2007 21:17:55 Alan Stern wrote: > On Fri, 26 Oct 2007, Maxim Levitsky wrote: > > > > > Looking through the dmfe code, I noticed yet another possible race. > > > > A race between the .suspend, and a timer that serves both as a watchdog, and link state detector. > > > > Again I need to prevent it from running during the suspend/resume, but how? > > > > > > > > I can use del_timer in .suspend, and mod_timer in .resume, but that doesn't protect against > > > > race with already running timer. > > > > I can use del_timer_sync, but it states that it is useless if timer re-enables itself, and I agree with that. > > > > In dmfe case the timer does re-enable itself. > > > > > > That comment isn't right. del_timer_sync works perfectly well even if > > > the timer routine re-enables itself, provided it stops doing so after a > > > small number of iterations. > > Thanks for the info. but.... > > Due to the "don't access the hardware, while powered-off" rule, I must know that the timer isn't running. > > and won't be. > > So what function to use (if possible) to be sure that the timer won't run anymore? > > (Taking in the account the fact that it re-enables itself) > > Use del_timer_sync(). It guarantees that when it returns, the timer > will be stopped and the timer routine will no longer be running on any > CPU. > Even if the timer re-enables itself, are you sure? > Alan Stern > > Best regards, Maxim Levitsky _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
