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From: Christoph Hellwig <hch@infradead.org>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH] mm, gpu: fix error when FOLL_MLOCK an unpresent page
Date: Mon, 30 Aug 2021 08:00:31 +0100	[thread overview]
Message-ID: <YSyCDxWWvKP2OthC@infradead.org> (raw)
In-Reply-To: <20210829011953.9051-1-laoar.shao@gmail.com>

On Sun, Aug 29, 2021 at 01:19:53AM +0000, Yafang Shao wrote:
> After some analyzation, I found it was caused by a bug in GUP.
> When the kernel module calls get_user_pages() with FOLL_MLOCK being set but
> FOLL_POPULATE being unset, if the page of the user addr isn't present, the

Which is not a valid way to call get_user_pages.  What we need to do is
to reject that case.  No-tree user does this so that bug is what ever
crap out of tree code you're using.


  reply	other threads:[~2021-08-30  7:00 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-29  1:19 [PATCH] mm, gpu: fix error when FOLL_MLOCK an unpresent page Yafang Shao
2021-08-30  7:00 ` Christoph Hellwig [this message]
2021-08-30  9:12   ` Yafang Shao
2021-08-30 10:08     ` Christoph Hellwig
2021-08-30 10:55       ` Yafang Shao
2021-08-31  1:36         ` Kirill A. Shutemov
2021-08-31 12:32           ` Yafang Shao

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