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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Jack Wang <jinpu.wang@profitbricks.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Hillf Danton <hillf.zj@alibaba-inc.com>,
	stable@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 1/3] thp: reduce indentation level in change_huge_pmd()
Date: Thu, 7 Dec 2017 13:05:01 +0100	[thread overview]
Message-ID: <20171207120501.GA6159@kroah.com> (raw)
In-Reply-To: <1512642172-7981-2-git-send-email-jinpu.wangl@profitbricks.com>

On Thu, Dec 07, 2017 at 11:22:50AM +0100, Jack Wang wrote:
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> 
> commit 0a85e51d37645e9ce57e5e1a30859e07810ed07c upstream.
> 
> Patch series "thp: fix few MADV_DONTNEED races"
> 
> For MADV_DONTNEED to work properly with huge pages, it's critical to not
> clear pmd intermittently unless you hold down_write(mmap_sem).
> 
> Otherwise MADV_DONTNEED can miss the THP which can lead to userspace
> breakage.
> 
> See example of such race in commit message of patch 2/4.
> 
> All these races are found by code inspection.  I haven't seen them
> triggered.  I don't think it's worth to apply them to stable@.
> 
> This patch (of 4):

What about all 4 of these?

And should this also go into 4.9?  I don't want to include fixes into
4.4-stable without them also being in 4.9-stable, as that would be a
regression for people upgrading.

thanks,

greg k-h

  reply	other threads:[~2017-12-07 12:04 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1512642172-7981-1-git-send-email-jinpu.wangl@profitbricks.com>
2017-12-07 10:22 ` [PATCH 1/3] thp: reduce indentation level in change_huge_pmd() Jack Wang
2017-12-07 12:05   ` Greg Kroah-Hartman [this message]
2017-12-07 12:25     ` Jinpu Wang
2017-12-12  8:32       ` Greg Kroah-Hartman
2017-12-07 10:22 ` [PATCH 2/3] thp: fix MADV_DONTNEED vs. numa balancing race Jack Wang
2017-12-07 10:22 ` [PATCH 3/3] mm: drop unused pmdp_huge_get_and_clear_notify() Jack Wang

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