Re: [PATCH 3/3] livepatch: Cleanup message handling in klp_try_switch_task()

[Kamalesh Babulal]

On Wed, Apr 24, 2019 at 08:48:58PM +0200, Miroslav Benes wrote:
> On Wed, 24 Apr 2019, Josh Poimboeuf wrote:
> 
[...]
> > >  	ret = save_stack_trace_tsk_reliable(task, &trace);
> > > -	WARN_ON_ONCE(ret == -ENOSYS);
> > > +	if (ret == -ENOSYS) {
> > > +		if (!enosys_warned) {
> > > +			printk_deferred(KERN_WARNING "%s: save_stack_trace_tsk_reliable() not supported on this architecture.\n",
> > > +					__func__);
> > > +			enosys_warned = 1;
> > > +		}
> > > +		return ret;
> > > +	}
> > 
> > We already have a similar printk in patch 1, so is this warning really
> > needed?
> 
> I don't think so. pr_warn() in klp_enable_patch() should be enough in my 
> opinion.
> 
> However,
> 
> if (ret == -ENOSYS)
> 	return ret;
> 
> would be justified, wouldn't it?
> 

Probably an one line comment on why we return, will be helpful.

-- 
Kamalesh