Re: [PATCH v6 1/1] MIPS: Fix idle VS timer enqueue

[Frederic Weisbecker]

Le Wed, Mar 19, 2025 at 12:07:07PM +0100, Thomas Bogendoerfer a écrit :
> On Sat, Mar 15, 2025 at 08:40:02PM +0100, Marco Crivellari wrote:
> > MIPS re-enables interrupts on its idle routine and performs
> > a TIF_NEED_RESCHED check afterwards before putting the CPU to sleep.
> > 
> > The IRQs firing between the check and the 'wait' instruction may set the
> > TIF_NEED_RESCHED flag. In order to deal with this possible race, IRQs
> > interrupting __r4k_wait() rollback their return address to the
> > beginning of __r4k_wait() so that TIF_NEED_RESCHED is checked
> > again before going back to sleep.
> > 
> > However idle IRQs can also queue timers that may require a tick
> > reprogramming through a new generic idle loop iteration but those timers
> > would go unnoticed here because __r4k_wait() only checks
> > TIF_NEED_RESCHED. It doesn't check for pending timers.
> 
> can you give a commit ID, when this change got introduced ?

That would be:

     Fixes: c65a5480ff29 ("[MIPS] Fix potential latency problem due to non-atomic cpu_wait.")