linux-kernel - Re: How to avoid spurious lockdep warnings?

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 for Android: free password hash cracker in your pocket

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

Date:	Sat, 22 Mar 2008 13:46:56 -0700
From:	Arjan van de Ven <arjan@...radead.org>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
Cc:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...e.hu>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: How to avoid spurious lockdep warnings?

On Thu, 20 Mar 2008 16:02:11 -0700
Jeremy Fitzhardinge <jeremy@...p.org> wrote:

> In a Xen system, when a new pagetable is about to be put in use it is 
> "pinned", meaning that each page in the pagetable is registered with
> the hypervisor.  This is done in arch/x86/xen/mmu.c:pin_page().
> 
> In order to make this efficient, the hypercalls for pinning are
> batched, so that multiple pages are submitted at once in a single
> multicall. While a page is batched pending the hypercall, its
> corresponding pte_lock is held.
> 
> This means that the code can end up holding multiple pte locks at
> once, though it is guaranteed to never try to hold the same lock at
> once. However, because these locks are in the same lock class, I get
> a spurious warning from lockdep.  Is there some way I can get rid of
> this warning?


what's the ordering guarantee between these locks ?


-- 
If you want to reach me at my work email, use arjan@...ux.intel.com
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
--
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/