linux-kernel - Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170228132820.GH3817@X58A-UD3R>
Date:   Tue, 28 Feb 2017 22:28:20 +0900
From:   Byungchul Park <byungchul.park@....com>
To:     Peter Zijlstra <peterz@...radead.org>
CC:     <mingo@...nel.org>, <tglx@...utronix.de>, <walken@...gle.com>,
        <boqun.feng@...il.com>, <kirill@...temov.name>,
        <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
        <iamjoonsoo.kim@....com>, <akpm@...ux-foundation.org>,
        <npiggin@...il.com>, <kernel-team@....com>
Subject: Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

On Tue, Feb 28, 2017 at 02:05:13PM +0100, Peter Zijlstra wrote:
> On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote:
> > +#define MAX_XHLOCKS_NR 64UL
> 
> > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE
> > +	if (tsk->xhlocks) {
> > +		void *tmp = tsk->xhlocks;
> > +		/* Disable crossrelease for current */
> > +		tsk->xhlocks = NULL;
> > +		vfree(tmp);
> > +	}
> > +#endif
> 
> > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE
> > +	p->xhlock_idx = 0;
> > +	p->xhlock_idx_soft = 0;
> > +	p->xhlock_idx_hard = 0;
> > +	p->xhlock_idx_nmi = 0;
> > +	p->xhlocks = vzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR);
> 
> I don't think we need vmalloc for this now.

Really? When is a better time to do it?

I think the time creating a task is the best time to initialize it. No?

> 
> > +	p->work_id = 0;
> > +#endif
> 
> > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE
> > +	if (p->xhlocks) {
> > +		void *tmp = p->xhlocks;
> > +		/* Diable crossrelease for current */
> > +		p->xhlocks = NULL;
> > +		vfree(tmp);
> > +	}
> > +#endif
> 
> Second instance of the same code, which would suggest using a function
> for this. Also, with a function you can loose the #ifdeffery.

Yes. It looks much better.

Thank you very much.