linux-kernel - Re: [PATCH 14/15] mm: numa: Flush TLB if NUMA hinting faults race with PTE scan update

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:	Tue, 03 Dec 2013 18:07:06 -0500
From:	Rik van Riel <riel@...hat.com>
To:	Mel Gorman <mgorman@...e.de>
CC:	Alex Thorlton <athorlton@....com>, Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 14/15] mm: numa: Flush TLB if NUMA hinting faults race
 with PTE scan update

On 12/03/2013 03:52 AM, Mel Gorman wrote:
> NUMA PTE updates and NUMA PTE hinting faults can race against each other. The
> setting of the NUMA bit defers the TLB flush to reduce overhead. NUMA
> hinting faults do not flush the TLB as X86 at least does not cache TLB
> entries for !present PTEs. However, in the event that the two race a NUMA
> hinting fault may return with the TLB in an inconsistent state between
> different processors. This patch detects potential for races between the
> NUMA PTE scanner and fault handler and will flush the TLB for the affected
> range if there is a race.
> 
> Signed-off-by: Mel Gorman <mgorman@...e.de>

> diff --git a/mm/migrate.c b/mm/migrate.c
> index 5dfd552..ccc814b 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1662,6 +1662,39 @@ void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd)
>  	smp_rmb();
>  }
>  
> +unsigned long numa_fault_prepare(struct mm_struct *mm)
> +{
> +	/* Paired with task_numa_work */
> +	smp_rmb();
> +	return mm->numa_next_reset;
> +}

The patch that introduces mm->numa_next_reset, and the
patch that increments it, seem to be missing from your
series...

-- 
All rights reversed
--
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/