linux-kernel - Re: [PATCH 3/4] cpuset: Fix unchecked calls to NODEMASK

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]

Date:	Thu, 17 Feb 2011 15:50:01 -0800
From:	Paul Menage <menage@...gle.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Li Zefan <lizf@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	David Rientjes <rientjes@...gle.com>,
	缪 勰 <miaox@...fujitsu.com>,
	linux-mm@...ck.org
Subject: Re: [PATCH 3/4] cpuset: Fix unchecked calls to NODEMASK_ALLOC()

On Thu, Feb 17, 2011 at 2:46 PM, Andrew Morton
<akpm@...ux-foundation.org> wrote:
> On Thu, 17 Feb 2011 09:50:09 +0800
> Li Zefan <lizf@...fujitsu.com> wrote:
>
>> +/*
>> + * In functions that can't propogate errno to users, to avoid declaring a
>> + * nodemask_t variable, and avoid using NODEMASK_ALLOC that can return
>> + * -ENOMEM, we use this global cpuset_mems.
>> + *
>> + * It should be used with cgroup_lock held.
>
> I'll do s/should/must/ - that would be a nasty bug.
>
> I'd be more comfortable about the maintainability of this optimisation
> if we had
>
>        WARN_ON(!cgroup_is_locked());
>
> at each site.
>

Agreed - that was my first thought on reading the patch. How about:

static nodemask_t *cpuset_static_nodemask() {
  static nodemask_t nodemask;
  WARN_ON(!cgroup_is_locked());
  return &nodemask;
}

and then just call cpuset_static_nodemask() in the various locations
being patched?

Paul
--
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/