linux-kernel - Re: [RFC 4/4] mm: Ignore cpuset enforcement when allocation flag has __GFP

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: <8216916c-c3f3-bad9-33cb-b0da2508f3d0@intel.com>
Date:   Mon, 28 Nov 2016 13:12:02 -0800
From:   Dave Hansen <dave.hansen@...el.com>
To:     Anshuman Khandual <khandual@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     mhocko@...e.com, vbabka@...e.cz, mgorman@...e.de,
        minchan@...nel.org, aneesh.kumar@...ux.vnet.ibm.com,
        bsingharora@...il.com, srikar@...ux.vnet.ibm.com,
        haren@...ux.vnet.ibm.com, jglisse@...hat.com
Subject: Re: [RFC 4/4] mm: Ignore cpuset enforcement when allocation flag has
 __GFP_THISNODE

On 11/22/2016 06:19 AM, Anshuman Khandual wrote:
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3715,7 +3715,7 @@ struct page *
>  		.migratetype = gfpflags_to_migratetype(gfp_mask),
>  	};
>  
> -	if (cpusets_enabled()) {
> +	if (cpusets_enabled() && !(alloc_mask & __GFP_THISNODE)) {
>  		alloc_mask |= __GFP_HARDWALL;
>  		alloc_flags |= ALLOC_CPUSET;
>  		if (!ac.nodemask)

This means now that any __GFP_THISNODE allocation can "escape" the
cpuset.  That seems like a pretty major change to how cpusets works.  Do
we know that *ALL* __GFP_THISNODE allocations are truly lacking in a
cpuset context that can be enforced?