Re: [RFC][PATCH v2 00/31] timers: Use del_timer_shutdown() before freeing timers

[Sebastian Andrzej Siewior]

On 2022-10-27 17:52:21 [+0200], Jason A. Donenfeld wrote:
> On Thu, Oct 27, 2022 at 11:05:25AM -0400, Steven Rostedt wrote:
…
> 
> FYI, there's a related issue with add_timer_on(), currently without a
> straight forward solution, in case you're curious, discussed with
> Sebastian and Sultan a few weeks ago. Pasting from that thread, the
> issue is:
…
…
> 
> It would be interesting if your patch fixed this case too. But maybe the
> above is unfixable (and rather niche anyway).

Haven't read the thread, yet, but the issue we talked about a few weeks
ago is unfixable. I plan to document this.
Eitherway CONFIG_DEBUG_OBJECTS_TIMERS should warn you here.

There are watchdogs (clocksource_watchdog()) which rotate CPUs and
invoke add_timer_on() from within the callback. This complicates
things.

> Jason

Sebastian