Re: [PATCH v3] mm: fix race between MADV_FREE reclaim and blkdev direct IO read
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2022-01-31 23:43:44
Also in:
linux-mm
On Mon, 31 Jan 2022 20:02:55 -0300 Mauricio Faria de Oliveira [off-list ref] wrote:
Problem:
=======
Userspace might read the zero-page instead of actual data from a
direct IO read on a block device if the buffers have been called
madvise(MADV_FREE) on earlier (this is discussed below) due to a
race between page reclaim on MADV_FREE and blkdev direct IO read.
...
Fixes: 802a3a92ad7a ("mm: reclaim MADV_FREE pages")Five years ago. As it doesn't seem urgent I targeted 5.18-rc1 for this, and added a cc:stable so it will trickle back into earlier trees. How does this plan sound?