linux-kernel - Re: [RFC][PATCH 2/6] lockdep: validate rcu_dereference() vs rcu_read

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: <20070919214110.5d832f28@lappy>
Date:	Wed, 19 Sep 2007 21:41:10 +0200
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	"Dmitry Torokhov" <dmitry.torokhov@...il.com>
Cc:	paulmck@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
	"Ingo Molnar" <mingo@...e.hu>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Nick Piggin" <nickpiggin@...oo.com.au>
Subject: Re: [RFC][PATCH 2/6] lockdep: validate rcu_dereference() vs
 rcu_read_lock()

On Wed, 19 Sep 2007 14:49:56 -0400 "Dmitry Torokhov"
<dmitry.torokhov@...il.com> wrote:

> On 9/19/07, Paul E. McKenney <paulmck@...ux.vnet.ibm.com> wrote:

> > PS to previous -- any problem with inserting rcu_read_lock() and
> > rcu_read_unlock() around the portion of the IRQ handler that has
> > these accesses?
> >
> 
> I guess I could but it is an extra lock that needs to be managed and
> given the fact that it is not really needed (other to make a newly
> developed tool happy) I am hestsant to do that.

As is, these sites are a bug in -rt and we'll need to fix them anyway.

As for the code you pointed me to, the i8042 driver, it seems to play
way to funny tricks for a simple 'slow' driver.

If you replace the spin_lock() + sync_sched(), with rcu_read_lock() +
rcu_call() it should work again without adding an extra lock.
-
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/