Re: [PATCH] mm: fix unexpected changes to {failslab|fail_page_alloc}.attr

[Qi Zheng]

On 2022/11/8 00:26, Jason Gunthorpe wrote:
> On Mon, Nov 07, 2022 at 11:05:42PM +0800, Qi Zheng wrote:
> > On 2022/11/7 20:42, Jason Gunthorpe wrote:
> > > On Mon, Nov 07, 2022 at 11:31:09AM +0800, Qi Zheng wrote:
> > >
> > > > @@ -31,9 +33,9 @@ bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
> > > >    		return false;
> > > >    	if (gfpflags & __GFP_NOWARN)
> > > > -		failslab.attr.no_warn = true;
> > > > +		flags |= FAULT_NOWARN;
> > >
> > > You should add a comment here about why this is required, to avoid
> > > deadlocking printk
> >
> > I think this comment should be placed where __GFP_NOWARN is specified
> > instead of here. What do you think? :)
>
> NOWARN is clear what it does, it is this specifically that is very
> subtle about avoiding deadlock aginst allocations triggered by
> printk/etc code.

Oh, maybe I understand your concern. Some people may think that this
is just a print of fault injection information, not a warning. I'll
add a comment explaining why in some cases there must be no printing.

Thanks,
Qi

> Jason

--
Thanks,
Qi