Merge branch 'close-race-in-freeing-special-fields-and-map-value'

Kumar Kartikeya Dwivedi says:

====================
Close race in freeing special fields and map value

There exists a race across various map types where the freeing of
special fields (tw, timer, wq, kptr, etc.) can be done eagerly when a
logical delete operation is done on a map value, such that the program
which continues to have access to such a map value can recreate the
fields and cause them to leak.

The set contains fixes for this case. It is a continuation of Mykyta's
previous attempt in [0], but applies to all fields. A test is included
which reproduces the bug reliably in absence of the fixes.

Local Storage Benchmarks
------------------------
Evaluation Setup: Benchmarked on a dual-socket Intel Xeon Gold 6348 (Ice
Lake) @ 2.60GHz (56 cores / 112 threads), with the CPU governor set to
performance. Bench was pinned to a single NUMA node throughout the test.

Benchmark comes from [1] using the following command:
./bench -p 1 local-storage-create --storage-type <socket,task> --batch-size <16,32,64>

Before the test, 10 runs of all cases ([socket|task] x 3 batch sizes x 7
iterations per batch size) are done to warm up and prime the machine.

Then, 3 runs of all cases are done (with and without the patch, across
reboots).

For each comparison, we have 21 samples, i.e. per batch size (e.g.
socket 16) of a given local storage, we have 3 runs x 7 iterations.

The statistics (mean, median, stddev) and t-test is done for each
scenario (local storage and batch size pair) individually (21 samples
for either case). All values are for local storage creations in thousand
creations / sec (k/s).

	       Baseline (without patch)               With patch                       Delta
     Case      Median        Mean   Std. Dev.   Median        Mean   Std. Dev.   Median       %
---------------------------------------------------------------------------------------------------
socket 16     432.026     431.941    1.047     431.347     431.953    1.635      -0.679    -0.16%
socket 32     432.641     432.818    1.535     432.488     432.302    1.508      -0.153    -0.04%
socket 64     431.504     431.996    1.337     429.145     430.326    2.469      -2.359    -0.55%
  task 16      38.816      39.382    1.456      39.657      39.337    1.831      +0.841    +2.17%
  task 32      38.815      39.644    2.690      38.721      39.122    1.636      -0.094    -0.24%
  task 64      37.562      38.080    1.701      39.554      38.563    1.689      +1.992    +5.30%

The cases for socket are within the range of noise, and improvements in task
local storage are due to high variance (CV ~4%-6% across batch sizes). The only
statistically significant case worth mentioning is socket with batch size 64
with p-value from t-test < 0.05, but the absolute difference is small (~2k/s).

TL;DR there doesn't appear to be any significant regression or improvement.

  [0]: https://lore.kernel.org/bpf/20260216131341.1285427-1-mykyta.yatsenko5@gmail.com
  [1]: https://lore.kernel.org/bpf/20260205222916.1788211-1-ameryhung@gmail.com

Changelog:
----------
v2 -> v3
v2: https://lore.kernel.org/bpf/20260227052031.3988575-1-memxor@gmail.com

 * Add syzbot Tested-by.
 * Add Amery's Reviewed-by.
 * Fix missing rcu_dereference_check() in __bpf_selem_free_rcu. (BPF CI Bot)
 * Remove migrate_disable() in bpf_selem_free_rcu. (Alexei)

v1 -> v2
v1: https://lore.kernel.org/bpf/20260225185121.2057388-1-memxor@gmail.com

 * Add Paul's Reviewed-by.
 * Fix use-after-free in accessing bpf_mem_alloc embedded in map. (syzbot CI)
 * Add benchmark numbers for local storage.
 * Add extra test case for per-cpu hashmap coverage with up to 16 refcount leaks.
 * Target bpf tree.
====================

Link: https://patch.msgid.link/20260227224806.646888-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

10 files changed, 179 insertions, 54 deletions

diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c
index 144f30e740e8..f355cf1c1a16 100644
--- a/kernel/bpf/arena.c
+++ b/kernel/bpf/arena.c
@@ -303,7 +303,7 @@ static long arena_map_update_elem(struct bpf_map *map, void *key,
 	return -EOPNOTSUPP;
 }
 
-static int arena_map_check_btf(const struct bpf_map *map, const struct btf *btf,
+static int arena_map_check_btf(struct bpf_map *map, const struct btf *btf,
 			       const struct btf_type *key_type, const struct btf_type *value_type)
 {
 	return 0;
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 26763df6134a..33de68c95ad8 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -548,7 +548,7 @@ static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
 	rcu_read_unlock();
 }
 
-static int array_map_check_btf(const struct bpf_map *map,
+static int array_map_check_btf(struct bpf_map *map,
 			       const struct btf *btf,
 			       const struct btf_type *key_type,
 			       const struct btf_type *value_type)
diff --git a/kernel/bpf/bloom_filter.c b/kernel/bpf/bloom_filter.c
index 35e1ddca74d2..b73336c976b7 100644
--- a/kernel/bpf/bloom_filter.c
+++ b/kernel/bpf/bloom_filter.c
@@ -180,7 +180,7 @@ static long bloom_map_update_elem(struct bpf_map *map, void *key,
 	return -EINVAL;
 }
 
-static int bloom_map_check_btf(const struct bpf_map *map,
+static int bloom_map_check_btf(struct bpf_map *map,
 			       const struct btf *btf,
 			       const struct btf_type *key_type,
 			       const struct btf_type *value_type)
diff --git a/kernel/bpf/bpf_insn_array.c b/kernel/bpf/bpf_insn_array.c
index c0286f25ca3c..a2f84afe6f7c 100644
--- a/kernel/bpf/bpf_insn_array.c
+++ b/kernel/bpf/bpf_insn_array.c
@@ -98,7 +98,7 @@ static long insn_array_delete_elem(struct bpf_map *map, void *key)
 	return -EINVAL;
 }
 
-static int insn_array_check_btf(const struct bpf_map *map,
+static int insn_array_check_btf(struct bpf_map *map,
 			      const struct btf *btf,
 			      const struct btf_type *key_type,
 			      const struct btf_type *value_type)
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index b28f07d3a0db..9c96a4477f81 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -107,14 +107,12 @@ static void __bpf_local_storage_free_trace_rcu(struct rcu_head *rcu)
 {
 	struct bpf_local_storage *local_storage;
 
-	/* If RCU Tasks Trace grace period implies RCU grace period, do
-	 * kfree(), else do kfree_rcu().
+	/*
+	 * RCU Tasks Trace grace period implies RCU grace period, do
+	 * kfree() directly.
 	 */
 	local_storage = container_of(rcu, struct bpf_local_storage, rcu);
-	if (rcu_trace_implies_rcu_gp())
-		kfree(local_storage);
-	else
-		kfree_rcu(local_storage, rcu);
+	kfree(local_storage);
 }
 
 /* Handle use_kmalloc_nolock == false */
@@ -138,10 +136,11 @@ static void bpf_local_storage_free_rcu(struct rcu_head *rcu)
 
 static void bpf_local_storage_free_trace_rcu(struct rcu_head *rcu)
 {
-	if (rcu_trace_implies_rcu_gp())
-		bpf_local_storage_free_rcu(rcu);
-	else
-		call_rcu(rcu, bpf_local_storage_free_rcu);
+	/*
+	 * RCU Tasks Trace grace period implies RCU grace period, do
+	 * kfree() directly.
+	 */
+	bpf_local_storage_free_rcu(rcu);
 }
 
 static void bpf_local_storage_free(struct bpf_local_storage *local_storage,
@@ -164,16 +163,29 @@ static void bpf_local_storage_free(struct bpf_local_storage *local_storage,
 			     bpf_local_storage_free_trace_rcu);
 }
 
-/* rcu tasks trace callback for use_kmalloc_nolock == false */
-static void __bpf_selem_free_trace_rcu(struct rcu_head *rcu)
+/* rcu callback for use_kmalloc_nolock == false */
+static void __bpf_selem_free_rcu(struct rcu_head *rcu)
 {
 	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage_map *smap;
 
 	selem = container_of(rcu, struct bpf_local_storage_elem, rcu);
-	if (rcu_trace_implies_rcu_gp())
-		kfree(selem);
-	else
-		kfree_rcu(selem, rcu);
+	/* bpf_selem_unlink_nofail may have already cleared smap and freed fields. */
+	smap = rcu_dereference_check(SDATA(selem)->smap, 1);
+
+	if (smap)
+		bpf_obj_free_fields(smap->map.record, SDATA(selem)->data);
+	kfree(selem);
+}
+
+/* rcu tasks trace callback for use_kmalloc_nolock == false */
+static void __bpf_selem_free_trace_rcu(struct rcu_head *rcu)
+{
+	/*
+	 * RCU Tasks Trace grace period implies RCU grace period, do
+	 * kfree() directly.
+	 */
+	__bpf_selem_free_rcu(rcu);
 }
 
 /* Handle use_kmalloc_nolock == false */
@@ -181,7 +193,7 @@ static void __bpf_selem_free(struct bpf_local_storage_elem *selem,
 			     bool vanilla_rcu)
 {
 	if (vanilla_rcu)
-		kfree_rcu(selem, rcu);
+		call_rcu(&selem->rcu, __bpf_selem_free_rcu);
 	else
 		call_rcu_tasks_trace(&selem->rcu, __bpf_selem_free_trace_rcu);
 }
@@ -195,37 +207,29 @@ static void bpf_selem_free_rcu(struct rcu_head *rcu)
 	/* The bpf_local_storage_map_free will wait for rcu_barrier */
 	smap = rcu_dereference_check(SDATA(selem)->smap, 1);
 
-	if (smap) {
-		migrate_disable();
+	if (smap)
 		bpf_obj_free_fields(smap->map.record, SDATA(selem)->data);
-		migrate_enable();
-	}
 	kfree_nolock(selem);
 }
 
 static void bpf_selem_free_trace_rcu(struct rcu_head *rcu)
 {
-	if (rcu_trace_implies_rcu_gp())
-		bpf_selem_free_rcu(rcu);
-	else
-		call_rcu(rcu, bpf_selem_free_rcu);
+	/*
+	 * RCU Tasks Trace grace period implies RCU grace period, do
+	 * kfree() directly.
+	 */
+	bpf_selem_free_rcu(rcu);
 }
 
 void bpf_selem_free(struct bpf_local_storage_elem *selem,
 		    bool reuse_now)
 {
-	struct bpf_local_storage_map *smap;
-
-	smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held());
-
 	if (!selem->use_kmalloc_nolock) {
 		/*
 		 * No uptr will be unpin even when reuse_now == false since uptr
 		 * is only supported in task local storage, where
 		 * smap->use_kmalloc_nolock == true.
 		 */
-		if (smap)
-			bpf_obj_free_fields(smap->map.record, SDATA(selem)->data);
 		__bpf_selem_free(selem, reuse_now);
 		return;
 	}
@@ -797,7 +801,7 @@ int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
 	return 0;
 }
 
-int bpf_local_storage_map_check_btf(const struct bpf_map *map,
+int bpf_local_storage_map_check_btf(struct bpf_map *map,
 				    const struct btf *btf,
 				    const struct btf_type *key_type,
 				    const struct btf_type *value_type)
@@ -958,10 +962,9 @@ restart:
 	 */
 	synchronize_rcu();
 
-	if (smap->use_kmalloc_nolock) {
-		rcu_barrier_tasks_trace();
-		rcu_barrier();
-	}
+	/* smap remains in use regardless of kmalloc_nolock, so wait unconditionally. */
+	rcu_barrier_tasks_trace();
+	rcu_barrier();
 	kvfree(smap->buckets);
 	bpf_map_area_free(smap);
 }
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 3b9d297a53be..bc6bc8bb871d 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -125,6 +125,11 @@ struct htab_elem {
 	char key[] __aligned(8);
 };
 
+struct htab_btf_record {
+	struct btf_record *record;
+	u32 key_size;
+};
+
 static inline bool htab_is_prealloc(const struct bpf_htab *htab)
 {
 	return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
@@ -457,6 +462,83 @@ static int htab_map_alloc_check(union bpf_attr *attr)
 	return 0;
 }
 
+static void htab_mem_dtor(void *obj, void *ctx)
+{
+	struct htab_btf_record *hrec = ctx;
+	struct htab_elem *elem = obj;
+	void *map_value;
+
+	if (IS_ERR_OR_NULL(hrec->record))
+		return;
+
+	map_value = htab_elem_value(elem, hrec->key_size);
+	bpf_obj_free_fields(hrec->record, map_value);
+}
+
+static void htab_pcpu_mem_dtor(void *obj, void *ctx)
+{
+	void __percpu *pptr = *(void __percpu **)obj;
+	struct htab_btf_record *hrec = ctx;
+	int cpu;
+
+	if (IS_ERR_OR_NULL(hrec->record))
+		return;
+
+	for_each_possible_cpu(cpu)
+		bpf_obj_free_fields(hrec->record, per_cpu_ptr(pptr, cpu));
+}
+
+static void htab_dtor_ctx_free(void *ctx)
+{
+	struct htab_btf_record *hrec = ctx;
+
+	btf_record_free(hrec->record);
+	kfree(ctx);
+}
+
+static int htab_set_dtor(struct bpf_htab *htab, void (*dtor)(void *, void *))
+{
+	u32 key_size = htab->map.key_size;
+	struct bpf_mem_alloc *ma;
+	struct htab_btf_record *hrec;
+	int err;
+
+	/* No need for dtors. */
+	if (IS_ERR_OR_NULL(htab->map.record))
+		return 0;
+
+	hrec = kzalloc(sizeof(*hrec), GFP_KERNEL);
+	if (!hrec)
+		return -ENOMEM;
+	hrec->key_size = key_size;
+	hrec->record = btf_record_dup(htab->map.record);
+	if (IS_ERR(hrec->record)) {
+		err = PTR_ERR(hrec->record);
+		kfree(hrec);
+		return err;
+	}
+	ma = htab_is_percpu(htab) ? &htab->pcpu_ma : &htab->ma;
+	bpf_mem_alloc_set_dtor(ma, dtor, htab_dtor_ctx_free, hrec);
+	return 0;
+}
+
+static int htab_map_check_btf(struct bpf_map *map, const struct btf *btf,
+			      const struct btf_type *key_type, const struct btf_type *value_type)
+{
+	struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
+
+	if (htab_is_prealloc(htab))
+		return 0;
+	/*
+	 * We must set the dtor using this callback, as map's BTF record is not
+	 * populated in htab_map_alloc(), so it will always appear as NULL.
+	 */
+	if (htab_is_percpu(htab))
+		return htab_set_dtor(htab, htab_pcpu_mem_dtor);
+	else
+		return htab_set_dtor(htab, htab_mem_dtor);
+}
+
 static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
 {
 	bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
@@ -2281,6 +2363,7 @@ const struct bpf_map_ops htab_map_ops = {
 	.map_seq_show_elem = htab_map_seq_show_elem,
 	.map_set_for_each_callback_args = map_set_for_each_callback_args,
 	.map_for_each_callback = bpf_for_each_hash_elem,
+	.map_check_btf = htab_map_check_btf,
 	.map_mem_usage = htab_map_mem_usage,
 	BATCH_OPS(htab),
 	.map_btf_id = &htab_map_btf_ids[0],
@@ -2303,6 +2386,7 @@ const struct bpf_map_ops htab_lru_map_ops = {
 	.map_seq_show_elem = htab_map_seq_show_elem,
 	.map_set_for_each_callback_args = map_set_for_each_callback_args,
 	.map_for_each_callback = bpf_for_each_hash_elem,
+	.map_check_btf = htab_map_check_btf,
 	.map_mem_usage = htab_map_mem_usage,
 	BATCH_OPS(htab_lru),
 	.map_btf_id = &htab_map_btf_ids[0],
@@ -2482,6 +2566,7 @@ const struct bpf_map_ops htab_percpu_map_ops = {
 	.map_seq_show_elem = htab_percpu_map_seq_show_elem,
 	.map_set_for_each_callback_args = map_set_for_each_callback_args,
 	.map_for_each_callback = bpf_for_each_hash_elem,
+	.map_check_btf = htab_map_check_btf,
 	.map_mem_usage = htab_map_mem_usage,
 	BATCH_OPS(htab_percpu),
 	.map_btf_id = &htab_map_btf_ids[0],
@@ -2502,6 +2587,7 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = {
 	.map_seq_show_elem = htab_percpu_map_seq_show_elem,
 	.map_set_for_each_callback_args = map_set_for_each_callback_args,
 	.map_for_each_callback = bpf_for_each_hash_elem,
+	.map_check_btf = htab_map_check_btf,
 	.map_mem_usage = htab_map_mem_usage,
 	BATCH_OPS(htab_lru_percpu),
 	.map_btf_id = &htab_map_btf_ids[0],
diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
index 1ccbf28b2ad9..8fca0c64f7b1 100644
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -364,7 +364,7 @@ static long cgroup_storage_delete_elem(struct bpf_map *map, void *key)
 	return -EINVAL;
 }
 
-static int cgroup_storage_check_btf(const struct bpf_map *map,
+static int cgroup_storage_check_btf(struct bpf_map *map,
 				    const struct btf *btf,
 				    const struct btf_type *key_type,
 				    const struct btf_type *value_type)
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index 1adeb4d3b8cf..0f57608b385d 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -751,7 +751,7 @@ free_stack:
 	return err;
 }
 
-static int trie_check_btf(const struct bpf_map *map,
+static int trie_check_btf(struct bpf_map *map,
 			  const struct btf *btf,
 			  const struct btf_type *key_type,
 			  const struct btf_type *value_type)
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index bd45dda9dc35..682a9f34214b 100644
--- a/kernel/bpf/memalloc.c
+++ b/kernel/bpf/memalloc.c
@@ -102,6 +102,8 @@ struct bpf_mem_cache {
 	int percpu_size;
 	bool draining;
 	struct bpf_mem_cache *tgt;
+	void (*dtor)(void *obj, void *ctx);
+	void *dtor_ctx;
 
 	/* list of objects to be freed after RCU GP */
 	struct llist_head free_by_rcu;
@@ -260,12 +262,14 @@ static void free_one(void *obj, bool percpu)
 	kfree(obj);
 }
 
-static int free_all(struct llist_node *llnode, bool percpu)
+static int free_all(struct bpf_mem_cache *c, struct llist_node *llnode, bool percpu)
 {
 	struct llist_node *pos, *t;
 	int cnt = 0;
 
 	llist_for_each_safe(pos, t, llnode) {
+		if (c->dtor)
+			c->dtor((void *)pos + LLIST_NODE_SZ, c->dtor_ctx);
 		free_one(pos, percpu);
 		cnt++;
 	}
@@ -276,7 +280,7 @@ static void __free_rcu(struct rcu_head *head)
 {
 	struct bpf_mem_cache *c = container_of(head, struct bpf_mem_cache, rcu_ttrace);
 
-	free_all(llist_del_all(&c->waiting_for_gp_ttrace), !!c->percpu_size);
+	free_all(c, llist_del_all(&c->waiting_for_gp_ttrace), !!c->percpu_size);
 	atomic_set(&c->call_rcu_ttrace_in_progress, 0);
 }
 
@@ -308,7 +312,7 @@ static void do_call_rcu_ttrace(struct bpf_mem_cache *c)
 	if (atomic_xchg(&c->call_rcu_ttrace_in_progress, 1)) {
 		if (unlikely(READ_ONCE(c->draining))) {
 			llnode = llist_del_all(&c->free_by_rcu_ttrace);
-			free_all(llnode, !!c->percpu_size);
+			free_all(c, llnode, !!c->percpu_size);
 		}
 		return;
 	}
@@ -417,7 +421,7 @@ static void check_free_by_rcu(struct bpf_mem_cache *c)
 	dec_active(c, &flags);
 
 	if (unlikely(READ_ONCE(c->draining))) {
-		free_all(llist_del_all(&c->waiting_for_gp), !!c->percpu_size);
+		free_all(c, llist_del_all(&c->waiting_for_gp), !!c->percpu_size);
 		atomic_set(&c->call_rcu_in_progress, 0);
 	} else {
 		call_rcu_hurry(&c->rcu, __free_by_rcu);
@@ -635,13 +639,13 @@ static void drain_mem_cache(struct bpf_mem_cache *c)
 	 * Except for waiting_for_gp_ttrace list, there are no concurrent operations
 	 * on these lists, so it is safe to use __llist_del_all().
 	 */
-	free_all(llist_del_all(&c->free_by_rcu_ttrace), percpu);
-	free_all(llist_del_all(&c->waiting_for_gp_ttrace), percpu);
-	free_all(__llist_del_all(&c->free_llist), percpu);
-	free_all(__llist_del_all(&c->free_llist_extra), percpu);
-	free_all(__llist_del_all(&c->free_by_rcu), percpu);
-	free_all(__llist_del_all(&c->free_llist_extra_rcu), percpu);
-	free_all(llist_del_all(&c->waiting_for_gp), percpu);
+	free_all(c, llist_del_all(&c->free_by_rcu_ttrace), percpu);
+	free_all(c, llist_del_all(&c->waiting_for_gp_ttrace), percpu);
+	free_all(c, __llist_del_all(&c->free_llist), percpu);
+	free_all(c, __llist_del_all(&c->free_llist_extra), percpu);
+	free_all(c, __llist_del_all(&c->free_by_rcu), percpu);
+	free_all(c, __llist_del_all(&c->free_llist_extra_rcu), percpu);
+	free_all(c, llist_del_all(&c->waiting_for_gp), percpu);
 }
 
 static void check_mem_cache(struct bpf_mem_cache *c)
@@ -680,6 +684,9 @@ static void check_leaked_objs(struct bpf_mem_alloc *ma)
 
 static void free_mem_alloc_no_barrier(struct bpf_mem_alloc *ma)
 {
+	/* We can free dtor ctx only once all callbacks are done using it. */
+	if (ma->dtor_ctx_free)
+		ma->dtor_ctx_free(ma->dtor_ctx);
 	check_leaked_objs(ma);
 	free_percpu(ma->cache);
 	free_percpu(ma->caches);
@@ -1014,3 +1021,32 @@ int bpf_mem_alloc_check_size(bool percpu, size_t size)
 
 	return 0;
 }
+
+void bpf_mem_alloc_set_dtor(struct bpf_mem_alloc *ma, void (*dtor)(void *obj, void *ctx),
+			    void (*dtor_ctx_free)(void *ctx), void *ctx)
+{
+	struct bpf_mem_caches *cc;
+	struct bpf_mem_cache *c;
+	int cpu, i;
+
+	ma->dtor_ctx_free = dtor_ctx_free;
+	ma->dtor_ctx = ctx;
+
+	if (ma->cache) {
+		for_each_possible_cpu(cpu) {
+			c = per_cpu_ptr(ma->cache, cpu);
+			c->dtor = dtor;
+			c->dtor_ctx = ctx;
+		}
+	}
+	if (ma->caches) {
+		for_each_possible_cpu(cpu) {
+			cc = per_cpu_ptr(ma->caches, cpu);
+			for (i = 0; i < NUM_CACHES; i++) {
+				c = &cc->cache[i];
+				c->dtor = dtor;
+				c->dtor_ctx = ctx;
+			}
+		}
+	}
+}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0378e83b4099..274039e36465 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1234,7 +1234,7 @@ int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size)
 }
 EXPORT_SYMBOL_GPL(bpf_obj_name_cpy);
 
-int map_check_no_btf(const struct bpf_map *map,
+int map_check_no_btf(struct bpf_map *map,
 		     const struct btf *btf,
 		     const struct btf_type *key_type,
 		     const struct btf_type *value_type)