Re: [PATCH] usb: musb: Fix runtime PM race in musb_queue_resume_work

[Paul Cercueil]

Hi,

Le lun. 17 août 2020 à 13:59, Tony Lindgren <tony@xxxxxxxxxxx> a 
écrit :
> * Paul Cercueil <paul@xxxxxxxxxxxxxxx> [200809 12:54]:
> >  musb_queue_resume_work() would call the provided callback if the 
> > runtime
> >  PM status was 'active'. Otherwise, it would enqueue the request if 
> > the
> >  hardware was still suspended (musb->is_runtime_suspended is true).
> >
> >  This causes a race with the runtime PM handlers, as it is possible 
> > to be
> >  in the case where the runtime PM status is not yet 'active', but the
> >  hardware has been awaken (PM resume function has been called).
> >
> >  When hitting the race, the resume work was not enqueued, which 
> > probably
> >  triggered other bugs further down the stack. For instance, a telnet
> >  connection on Ingenic SoCs would result in a 50/50 chance of a
> >  segmentation fault somewhere in the musb code.
> >
> >  Rework the code so that either we call the callback directly if
> >  (musb->is_runtime_suspended == 0), or enqueue the query otherwise.
>
> Yes we should use is_runtime_suspended, thanks for fixing it.
> Things still work for me so:
>
> Reviewed-by: Tony Lindgren <tony@xxxxxxxxxxx>
> Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>

Bin, can you take this patch?

Thanks,
-Paul