From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, aquini@redhat.com,
cmaiolino@redhat.com, david@fromorbit.com, esandeen@redhat.com,
hsiangkao@redhat.com, linux-mm@kvack.org,
mm-commits@vger.kernel.org, shy828301@gmail.com,
stable@vger.kernel.org, torvalds@linux-foundation.org,
willy@infradead.org, ying.huang@intel.com
Subject: [patch 1/9] mm, THP, swap: fix allocating cluster for swapfile by mistake
Date: Fri, 25 Sep 2020 21:19:01 -0700 [thread overview]
Message-ID: <20200926041901.P-A_BQZ2V%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200925211725.0fea54be9e9715486efea21f@linux-foundation.org>
From: Gao Xiang <hsiangkao@redhat.com>
Subject: mm, THP, swap: fix allocating cluster for swapfile by mistake
SWP_FS is used to make swap_{read,write}page() go through the filesystem,
and it's only used for swap files over NFS. So, !SWP_FS means non NFS for
now, it could be either file backed or device backed. Something similar
goes with legacy SWP_FILE.
So in order to achieve the goal of the original patch, SWP_BLKDEV should
be used instead.
FS corruption can be observed with SSD device + XFS + fragmented swapfile
due to CONFIG_THP_SWAP=y.
I reproduced the issue with the following details:
Environment:
QEMU + upstream kernel + buildroot + NVMe (2 GB)
Kernel config:
CONFIG_BLK_DEV_NVME=y
CONFIG_THP_SWAP=y
Some reproducable steps:
mkfs.xfs -f /dev/nvme0n1
mkdir /tmp/mnt
mount /dev/nvme0n1 /tmp/mnt
bs="32k"
sz="1024m" # doesn't matter too much, I also tried 16m
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -F -S 0 -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fsync" /tmp/mnt/sw
mkswap /tmp/mnt/sw
swapon /tmp/mnt/sw
stress --vm 2 --vm-bytes 600M # doesn't matter too much as well
Symptoms:
- FS corruption (e.g. checksum failure)
- memory corruption at: 0xd2808010
- segfault
Link: https://lkml.kernel.org/r/20200820045323.7809-1-hsiangkao@redhat.com
Fixes: f0eea189e8e9 ("mm, THP, swap: Don't allocate huge cluster for file backed swap device")
Fixes: 38d8b4e6bdc8 ("mm, THP, swap: delay splitting THP during swap out")
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Eric Sandeen <esandeen@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/swapfile.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/swapfile.c~mm-thp-swap-fix-allocating-cluster-for-swapfile-by-mistake
+++ a/mm/swapfile.c
@@ -1078,7 +1078,7 @@ start_over:
goto nextsi;
}
if (size == SWAPFILE_CLUSTER) {
- if (!(si->flags & SWP_FS))
+ if (si->flags & SWP_BLKDEV)
n_ret = swap_alloc_cluster(si, swp_entries);
} else
n_ret = scan_swap_map_slots(si, SWAP_HAS_CACHE,
_
next prev parent reply other threads:[~2020-09-26 4:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-26 4:17 incoming Andrew Morton
2020-09-26 4:19 ` Andrew Morton [this message]
2020-09-26 4:19 ` [patch 2/9] mm: memcontrol: fix missing suffix of workingset_restore Andrew Morton
2020-09-26 4:19 ` [patch 3/9] mm/gup: fix gup_fast with dynamic page table folding Andrew Morton
2020-09-26 4:19 ` [patch 4/9] mm/migrate: correct thp migration stats Andrew Morton
2020-09-26 4:19 ` [patch 5/9] lib/string.c: implement stpcpy Andrew Morton
2020-09-26 4:19 ` [patch 6/9] lib/memregion.c: include memregion.h Andrew Morton
2020-09-26 4:19 ` [patch 7/9] arch/x86/lib/usercopy_64.c: fix __copy_user_flushcache() cache writeback Andrew Morton
2020-09-26 4:19 ` [patch 8/9] mm: replace memmap_context by meminit_context Andrew Morton
[not found] ` <CAHk-=wjcg4ni8_zhGDS9vTQQYM-3ZBg4hGF7Ot9MzW5F2o7mpA@mail.gmail.com>
2020-09-29 20:37 ` Andrew Morton
2020-09-26 4:19 ` [patch 9/9] mm: don't rely on system state to detect hot-plug operations Andrew Morton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200926041901.P-A_BQZ2V%akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=aquini@redhat.com \
--cc=cmaiolino@redhat.com \
--cc=david@fromorbit.com \
--cc=esandeen@redhat.com \
--cc=hsiangkao@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mm-commits@vger.kernel.org \
--cc=shy828301@gmail.com \
--cc=stable@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=willy@infradead.org \
--cc=ying.huang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).