linux-kernel - Re: [PATCH v2 03/17] signal: make may_ptrace

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Date:   Fri, 1 Jun 2018 18:00:29 +0200
From:   Christian Brauner <christian@...uner.io>
To:     Oleg Nesterov <oleg@...hat.com>
Cc:     linux-kernel@...r.kernel.org, ebiederm@...ssion.com,
        gregkh@...uxfoundation.org, mingo@...nel.org,
        james.morris@...rosoft.com, keescook@...omium.org,
        peterz@...radead.org, sds@...ho.nsa.gov, viro@...iv.linux.org.uk,
        akpm@...ux-foundation.org
Subject: Re: [PATCH v2 03/17] signal: make may_ptrace_stop() return bool

On Fri, Jun 01, 2018 at 05:56:12PM +0200, Oleg Nesterov wrote:
> On 06/01, Christian Brauner wrote:
> >
> > may_ptrace_stop() already behaves like a boolean function. Let's actually
> > declare it as such too.
> 
> OK. Then probably this patch should only make it return bool and do nothing else?
> 
> > -	if (unlikely(current->mm->core_state) &&
> > -	    unlikely(current->mm == current->parent->mm))
> > -		return 0;
> > +	if (likely(!current->mm->core_state ||
> > +		   current->mm != current->parent->mm))
> > +		return false;
> 
> this is wrong.

This was a suggestion by Al. I just took it over and may have messed it
up while doing so. I'll remove this.

Christian