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authorTuo Li <islituo@gmail.com>2023-06-13 11:06:37 +0800
committerAndreas Gruenbacher <agruenba@redhat.com>2023-06-13 14:34:17 +0200
commit6fa0a72cbbe45db4ed967a51f9e6f4e3afe61d20 (patch)
tree7b58645c89238d5b07ebceaca623200069eb198a /fs/gfs2
parentc8ed1b35931245087968fd95b2ec3dfc50f77769 (diff)
gfs2: Fix possible data races in gfs2_show_options()
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->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. Further changes by Andreas: - Don't hold the spin lock over the seq_printf operations. Reported-by: BassCheck <bass@buaa.edu.cn> Signed-off-by: Tuo Li <islituo@gmail.com> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Diffstat (limited to 'fs/gfs2')
-rw-r--r--fs/gfs2/super.c26
1 files changed, 15 insertions, 11 deletions
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 3a7e7c31eb9c..c89b28030495 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1004,7 +1004,14 @@ static int gfs2_show_options(struct seq_file *s, struct dentry *root)
{
struct gfs2_sbd *sdp = root->d_sb->s_fs_info;
struct gfs2_args *args = &sdp->sd_args;
- int val;
+ unsigned int logd_secs, statfs_slow, statfs_quantum, quota_quantum;
+
+ spin_lock(&sdp->sd_tune.gt_spin);
+ logd_secs = sdp->sd_tune.gt_logd_secs;
+ quota_quantum = sdp->sd_tune.gt_quota_quantum;
+ statfs_quantum = sdp->sd_tune.gt_statfs_quantum;
+ statfs_slow = sdp->sd_tune.gt_statfs_slow;
+ spin_unlock(&sdp->sd_tune.gt_spin);
if (is_ancestor(root, sdp->sd_master_dir))
seq_puts(s, ",meta");
@@ -1059,17 +1066,14 @@ static int gfs2_show_options(struct seq_file *s, struct dentry *root)
}
if (args->ar_discard)
seq_puts(s, ",discard");
- val = sdp->sd_tune.gt_logd_secs;
- if (val != 30)
- seq_printf(s, ",commit=%d", val);
- val = sdp->sd_tune.gt_statfs_quantum;
- if (val != 30)
- seq_printf(s, ",statfs_quantum=%d", val);
- else if (sdp->sd_tune.gt_statfs_slow)
+ if (logd_secs != 30)
+ seq_printf(s, ",commit=%d", logd_secs);
+ if (statfs_quantum != 30)
+ seq_printf(s, ",statfs_quantum=%d", statfs_quantum);
+ else if (statfs_slow)
seq_puts(s, ",statfs_quantum=0");
- val = sdp->sd_tune.gt_quota_quantum;
- if (val != 60)
- seq_printf(s, ",quota_quantum=%d", val);
+ if (quota_quantum != 60)
+ seq_printf(s, ",quota_quantum=%d", quota_quantum);
if (args->ar_statfs_percent)
seq_printf(s, ",statfs_percent=%d", args->ar_statfs_percent);
if (args->ar_errors != GFS2_ERRORS_DEFAULT) {