The variable kfence_metadata is initialized in kfence_init_pool(), then, it is
not initialized if kfence is disabled after booting. In this case, kfence_metadata
will be used (e.g. ->lock and ->state fields) without initialization when reading
/sys/kernel/debug/kfence/objects. There will be a warning if you enable
CONFIG_DEBUG_SPINLOCK. Fix it by creating debugfs files when necessary.
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
mm/kfence/core.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 5349c37a5dac..79c94ee55f97 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -726,10 +726,14 @@ static const struct seq_operations objects_sops = {
};
DEFINE_SEQ_ATTRIBUTE(objects);
-static int __init kfence_debugfs_init(void)
+static int kfence_debugfs_init(void)
{
- struct dentry *kfence_dir = debugfs_create_dir("kfence", NULL);
+ struct dentry *kfence_dir;
+ if (!READ_ONCE(kfence_enabled))
+ return 0;
+
+ kfence_dir = debugfs_create_dir("kfence", NULL);
debugfs_create_file("stats", 0444, kfence_dir, NULL, &stats_fops);
debugfs_create_file("objects", 0400, kfence_dir, NULL, &objects_fops);
return 0;
@@ -883,6 +887,8 @@ static int kfence_init_late(void)
}
kfence_init_enable();
+ kfence_debugfs_init();
+
return 0;
}
--
2.11.0
