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authorMuchun Song <songmuchun@bytedance.com>2023-03-15 11:44:41 +0800
committerAndrew Morton <akpm@linux-foundation.org>2023-03-23 17:18:35 -0700
commit1c86a188e03156223a34d09ce290b49bd4dd0403 (patch)
treea5d6a977efb9fdb8aac4bf556d6acd93f0d2401f /mm
parent13684e966d46283e0e89b6a4941596dc52b18bf3 (diff)
mm: kfence: fix using kfence_metadata without initialization in show_object()
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. Link: https://lkml.kernel.org/r/20230315034441.44321-1-songmuchun@bytedance.com Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Tested-by: Marco Elver <elver@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jann Horn <jannh@google.com> Cc: SeongJae Park <sjpark@amazon.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/kfence/core.c10
1 files 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;
}