From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: darrick.wong@oracle.com
Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] fs: xfs: fix a possible data race in xfs_inode_set_reclaim_tag()
Date: Tue, 5 May 2020 00:15:30 +0800 [thread overview]
Message-ID: <20200504161530.14059-1-baijiaju1990@gmail.com> (raw)
We find that xfs_inode_set_reclaim_tag() and xfs_reclaim_inode() are
concurrently executed at runtime in the following call contexts:
Thread1:
xfs_fs_put_super()
xfs_unmountfs()
xfs_rtunmount_inodes()
xfs_irele()
xfs_fs_destroy_inode()
xfs_inode_set_reclaim_tag()
Thread2:
xfs_reclaim_worker()
xfs_reclaim_inodes()
xfs_reclaim_inodes_ag()
xfs_reclaim_inode()
In xfs_inode_set_reclaim_tag():
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
...
spin_lock(&ip->i_flags_lock);
In xfs_reclaim_inode():
spin_lock(&ip->i_flags_lock);
...
ip->i_ino = 0;
spin_unlock(&ip->i_flags_lock);
Thus, a data race can occur for ip->i_ino.
To fix this data race, the spinlock ip->i_flags_lock is used to protect
the access to ip->i_ino in xfs_inode_set_reclaim_tag().
This data race is found by our concurrency fuzzer.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
fs/xfs/xfs_icache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 8bf1d15be3f6..a2de08222ff5 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -229,9 +229,9 @@ xfs_inode_set_reclaim_tag(
struct xfs_mount *mp = ip->i_mount;
struct xfs_perag *pag;
+ spin_lock(&ip->i_flags_lock);
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
spin_lock(&pag->pag_ici_lock);
- spin_lock(&ip->i_flags_lock);
radix_tree_tag_set(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino),
XFS_ICI_RECLAIM_TAG);
--
2.17.1
next reply other threads:[~2020-05-04 16:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-04 16:15 Jia-Ju Bai [this message]
2020-05-04 21:25 ` [PATCH] fs: xfs: fix a possible data race in xfs_inode_set_reclaim_tag() Dave Chinner
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=20200504161530.14059-1-baijiaju1990@gmail.com \
--to=baijiaju1990@gmail.com \
--cc=darrick.wong@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.