linux-kernel - Re: [PATCH 1/2] mm: fix bugs of mpol_rebind

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: <alpine.DEB.2.00.1004221415090.25350@chino.kir.corp.google.com>
Date:	Thu, 22 Apr 2010 14:20:23 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Miao Xie <miaox@...fujitsu.com>
cc:	Lee Schermerhorn <lee.schermerhorn@...com>,
	Nick Piggin <npiggin@...e.de>, Paul Menage <menage@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linux-Kernel <linux-kernel@...r.kernel.org>,
	Linux-MM <linux-mm@...ck.org>
Subject: Re: [PATCH 1/2] mm: fix bugs of mpol_rebind_nodemask()

On Thu, 22 Apr 2010, Miao Xie wrote:

> - local variable might be an empty nodemask, so must be checked before setting
>   pol->v.nodes to it.
> 
> - nodes_remap() may cause the weight of pol->v.nodes being monotonic decreasing.
>   and never become large even we pass a nodemask with large weight after
>   ->v.nodes become little.
> 

That's always been the intention of rebinding a mempolicy nodemask: we 
remap the current mempolicy nodes over the new nodemask given the set of 
allowed nodes.  The nodes_remap() shouldn't be removed.

> this patch fixes these two problem.
> 
> Signed-off-by: Miao Xie <miaox@...fujitsu.com>
> ---
>  mm/mempolicy.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 08f40a2..03ba9fc 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -291,12 +291,15 @@ static void mpol_rebind_nodemask(struct mempolicy *pol,
>  	else if (pol->flags & MPOL_F_RELATIVE_NODES)
>  		mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
>  	else {
> -		nodes_remap(tmp, pol->v.nodes, pol->w.cpuset_mems_allowed,
> -			    *nodes);
> +		tmp = *nodes;
>  		pol->w.cpuset_mems_allowed = *nodes;
>  	}
>  
> -	pol->v.nodes = tmp;
> +	if (nodes_empty(tmp))
> +		pol->v.nodes = *nodes;
> +	else
> +		pol->v.nodes = tmp;
> +
>  	if (!node_isset(current->il_next, tmp)) {
>  		current->il_next = next_node(current->il_next, tmp);
>  		if (current->il_next >= MAX_NUMNODES)
--
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/