From: Tuo Li <islituo@gmail.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [PATCH] gfs2: Fix possible data races in gfs2_show_options()
Date: Tue, 13 Jun 2023 11:06:37 +0800 [thread overview]
Message-ID: <20230613030637.2934730-1-islituo@gmail.com> (raw)
Some fields such as gt_logd_secs of the struct gfs2_tune are accessed
without holding the lock gt_spin in gfs2_show_options():
val = sdp->sd_tune.gt_logd_secs;
if (val != 30)
seq_printf(s, ",commit=%d", val);
And thus can cause data races when gfs2_show_options() and other functions
such as gfs2_reconfigure() are concurrently executed:
spin_lock(>->gt_spin);
gt->gt_logd_secs = newargs->ar_commit;
To fix these possible data races, the lock sdp->sd_tune.gt_spin is
acquired before accessing the fields of gfs2_tune and released after these
accesses.
Reported-by: BassCheck <bass@buaa.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
fs/gfs2/super.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index a84bf6444bba..671adf38fe03 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1059,6 +1059,7 @@ static int gfs2_show_options(struct seq_file *s, struct dentry *root)
}
if (args->ar_discard)
seq_puts(s, ",discard");
+ spin_lock(&sdp->sd_tune.gt_spin);
val = sdp->sd_tune.gt_logd_secs;
if (val != 30)
seq_printf(s, ",commit=%d", val);
@@ -1070,6 +1071,7 @@ static int gfs2_show_options(struct seq_file *s, struct dentry *root)
val = sdp->sd_tune.gt_quota_quantum;
if (val != 60)
seq_printf(s, ",quota_quantum=%d", val);
+ spin_unlock(&sdp->sd_tune.gt_spin);
if (args->ar_statfs_percent)
seq_printf(s, ",statfs_percent=%d", args->ar_statfs_percent);
if (args->ar_errors != GFS2_ERRORS_DEFAULT) {
--
2.34.1
next reply other threads:[~2023-06-13 3:06 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-13 3:06 Tuo Li [this message]
2023-06-13 12:40 ` [Cluster-devel] [PATCH] gfs2: Fix possible data races in gfs2_show_options() Andreas Gruenbacher
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