linux-kernel - Re: [PATCH] context_tracking: Add comments on interface and internals

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: <20121213150015.e497a585.akpm@linux-foundation.org>
Date:	Thu, 13 Dec 2012 15:00:15 -0800
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Ingo Molnar <mingo@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Gilad Ben-Yossef <gilad@...yossef.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Steven Rostedt <rostedt@...dmis.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Li Zhong <zhong@...ux.vnet.ibm.com>
Subject: Re: [PATCH] context_tracking: Add comments on interface and
 internals

On Thu, 13 Dec 2012 23:50:23 +0100
Frederic Weisbecker <fweisbec@...il.com> wrote:

> >
> >> + * This call supports re-entrancy.
> >
> > Presumably the explanation for user_exit() applies here.
> 
> Not sure what you mean here.

It's unclear what it means to say "user_enter() supports reentrancy". 
I mean, zillions of kernel functions are surely reentrant - so what? 
It appears that you had something in mind when pointing this out, but
what was it?  The comment over user_exit() appears to tell us.

> > It's mainly this bit which makes me wonder why the code is in lib/.  Is
> > there any conceivable prospect that any other subsystem will use this
> > code for anything?
> 
> So that's because of that cputime accounting on dynticks CPUs which
> will need to know about user/kernel transitions. I'm preparing that
> for the 3.9 merge window.

Oh.  That's really the entire reason for the patch and should have been
in the changelog!
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/