linux-kernel - [PATCH AUTOSEL 6.11 01/76] bpf: Call the missed btf_record

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Message-ID: <20241004181828.3669209-1-sashal@kernel.org>
Date: Fri,  4 Oct 2024 14:16:18 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Hou Tao <houtao1@...wei.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Alexei Starovoitov <ast@...nel.org>,
	Sasha Levin <sashal@...nel.org>,
	daniel@...earbox.net,
	andrii@...nel.org,
	bpf@...r.kernel.org
Subject: [PATCH AUTOSEL 6.11 01/76] bpf: Call the missed btf_record_free() when map creation fails

From: Hou Tao <houtao1@...wei.com>

[ Upstream commit 87e9675a0dfd0bf4a36550e4a0e673038ec67aee ]

When security_bpf_map_create() in map_create() fails, map_create() will
call btf_put() and ->map_free() callback to free the map. It doesn't
free the btf_record of map value, so add the missed btf_record_free()
when map creation fails.

However btf_record_free() needs to be called after ->map_free() just
like bpf_map_free_deferred() did, because ->map_free() may use the
btf_record to free the special fields in preallocated map value. So
factor out bpf_map_free() helper to free the map, btf_record, and btf
orderly and use the helper in both map_create() and
bpf_map_free_deferred().

Signed-off-by: Hou Tao <houtao1@...wei.com>
Acked-by: Jiri Olsa <jolsa@...nel.org>
Link: https://lore.kernel.org/r/20240912012845.3458483-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/bpf/syscall.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index bf6c5f685ea22..931ae9ad78149 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -733,15 +733,11 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj)
 	}
 }
 
-/* called from workqueue */
-static void bpf_map_free_deferred(struct work_struct *work)
+static void bpf_map_free(struct bpf_map *map)
 {
-	struct bpf_map *map = container_of(work, struct bpf_map, work);
 	struct btf_record *rec = map->record;
 	struct btf *btf = map->btf;
 
-	security_bpf_map_free(map);
-	bpf_map_release_memcg(map);
 	/* implementation dependent freeing */
 	map->ops->map_free(map);
 	/* Delay freeing of btf_record for maps, as map_free
@@ -760,6 +756,16 @@ static void bpf_map_free_deferred(struct work_struct *work)
 	btf_put(btf);
 }
 
+/* called from workqueue */
+static void bpf_map_free_deferred(struct work_struct *work)
+{
+	struct bpf_map *map = container_of(work, struct bpf_map, work);
+
+	security_bpf_map_free(map);
+	bpf_map_release_memcg(map);
+	bpf_map_free(map);
+}
+
 static void bpf_map_put_uref(struct bpf_map *map)
 {
 	if (atomic64_dec_and_test(&map->usercnt)) {
@@ -1411,8 +1417,7 @@ static int map_create(union bpf_attr *attr)
 free_map_sec:
 	security_bpf_map_free(map);
 free_map:
-	btf_put(map->btf);
-	map->ops->map_free(map);
+	bpf_map_free(map);
 put_token:
 	bpf_token_put(token);
 	return err;
-- 
2.43.0