Re: [syzbot] [mm?] WARNING in mas_nomem

On 26/08/07 09:19AM, Liam R. Howlett wrote:
> On 26/08/06 12:48PM, Jason Gunthorpe wrote:
> > On Thu, Aug 06, 2026 at 10:29:27AM -0400, Liam R. Howlett wrote:
> > 
> > > @@ -5609,8 +5612,7 @@ void *mas_store(struct ma_state *mas, void *entry)
> > >  		goto store;
> > >  
> > >  	mas_alloc_nodes(mas, GFP_NOWAIT);
> > > -	if (mas_is_err(mas))
> > > -		return NULL;
> > > +	mas_nomem(mas, GFP_KERNEL | __GFP_NOFAIL);
> > 
> > It still feels really weird to ignore the return code from mas_nomem..
> > 
> >  void mas_nomem_nofail() 
> 
> Sure, that's fair.
> 
> > 
> > ? and maybe it can have a WARN_ON
> 
> 
> The warning would never trigger.  If the allocation fails with nofail,
> then you'd never reach the warning.

Upon rereading my reply, I don't think it was clear what's going to
happen here.

If there's really no memory and no reserves, then we're going to panic
on trying to allocate.  So, even if I rewrite this to have a void
function to print a warning, it will never trigger, at that point why
have another function?  Are you looking to document what's happening in
the code with this?  If so, maybe a comment would be better.

Thanks,
Liam