linux-kernel - Re: [PATCH] mm: fix kernel BUG at huge

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:	Sun, 16 Dec 2012 19:00:12 -0800
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Hugh Dickins <hughd@...gle.com>
Cc:	Mel Gorman <mgorman@...e.de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Ingo Molnar <mingo@...nel.org>, Rik van Riel <riel@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Paul Turner <pjt@...gle.com>, Hillf Danton <dhillf@...il.com>,
	David Rientjes <rientjes@...gle.com>,
	Lee Schermerhorn <Lee.Schermerhorn@...com>,
	Alex Shi <lkml.alex@...il.com>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
	Aneesh Kumar <aneesh.kumar@...ux.vnet.ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm: fix kernel BUG at huge_memory.c:1474!

On Sun, Dec 16, 2012 at 6:56 PM, Hugh Dickins <hughd@...gle.com> wrote:
> Andrea's autonuma-benchmark numa01 hits kernel BUG at huge_memory.c:1474!
> in change_huge_pmd called from change_protection from change_prot_numa
> from task_numa_work.
>
> That BUG, introduced in the huge zero page commit cad7f613c4d0 ("thp:
> change_huge_pmd(): make sure we don't try to make a page writable")
> was trying to verify that newprot never adds write permission to an
> anonymous huge page; but Automatic NUMA Balancing's 4b10e7d562c9 ("mm:
> mempolicy: Implement change_prot_numa() in terms of change_protection()")
> adds a new prot_numa path into change_huge_pmd(), which makes no use of
> the newprot provided, and may retain the write bit in the pmd.

Ok. I did wonder about that particular conflict, but it looked like
neither case was writable, so I resolved it wrongly, and it worked for
me, but then I don't have any numa setups, nor do I even enable it..

Thanks,

                Linus
--
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/