Store ftrace hash buckets in the ftrace_hash allocation instead of
allocating the bucket array separately.

This keeps the bucket storage tied to the hash lifetime and simplifies
the allocation and cleanup paths.

Assisted-by: Codex:GPT-5.5
Signed-off-by: Rosen Penev <[email protected]>
---
 kernel/trace/ftrace.c | 17 ++---------------
 kernel/trace/trace.h  |  2 +-
 2 files changed, 3 insertions(+), 16 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b2611de3f594..25a9dca290dd 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1082,10 +1082,7 @@ struct ftrace_func_probe {
  * it all the time. These are in a read only section such that if
  * anyone does try to modify it, it will cause an exception.
  */
-static const struct hlist_head empty_buckets[1];
-static const struct ftrace_hash empty_hash = {
-       .buckets = (struct hlist_head *)empty_buckets,
-};
+static const struct ftrace_hash empty_hash = {};
 #define EMPTY_HASH     ((struct ftrace_hash *)&empty_hash)
 
 struct ftrace_ops global_ops = {
@@ -1295,7 +1292,6 @@ void free_ftrace_hash(struct ftrace_hash *hash)
        if (!hash || hash == EMPTY_HASH)
                return;
        ftrace_hash_clear(hash);
-       kfree(hash->buckets);
        kfree(hash);
 }
 
@@ -1333,20 +1329,11 @@ EXPORT_SYMBOL_GPL(ftrace_free_filter);
 struct ftrace_hash *alloc_ftrace_hash(int size_bits)
 {
        struct ftrace_hash *hash;
-       int size;
 
-       hash = kzalloc_obj(*hash);
+       hash = kzalloc_flex(*hash, buckets, BIT(size_bits));
        if (!hash)
                return NULL;
 
-       size = 1 << size_bits;
-       hash->buckets = kzalloc_objs(*hash->buckets, size);
-
-       if (!hash->buckets) {
-               kfree(hash);
-               return NULL;
-       }
-
        hash->size_bits = size_bits;
 
        return hash;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 80fe152af1dd..5a3f81f17317 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1000,10 +1000,10 @@ enum {
 
 struct ftrace_hash {
        unsigned long           size_bits;
-       struct hlist_head       *buckets;
        unsigned long           count;
        unsigned long           flags;
        struct rcu_head         rcu;
+       struct hlist_head       buckets[];
 };
 
 struct ftrace_func_entry *
-- 
2.54.0


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