From: Hou Tao Date: Wed, 8 Jan 2025 01:07:19 +0000 (+0800) Subject: bpf: Disable migration when destroying sock storage X-Git-Tag: v6.14-rc1~133^2~18^2~9 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=7d1032d1e3031ef38d1a360380d755f75cb639b8;p=linux-block.git bpf: Disable migration when destroying sock storage When destroying sock storage, it invokes bpf_local_storage_destroy() to remove all storage elements saved in the sock storage. The destroy procedure will call bpf_selem_free() to free the element, and bpf_selem_free() calls bpf_obj_free_fields() to free the special fields in map value (e.g., kptr). Since kptrs may be allocated from bpf memory allocator, migrate_{disable|enable} pairs are necessary for the freeing of these kptrs. To simplify reasoning about when migrate_disable() is needed for the freeing of these dynamically-allocated kptrs, let the caller to guarantee migration is disabled before invoking bpf_obj_free_fields(). Therefore, the patch adds migrate_{disable|enable} pair in bpf_sock_storage_free(). The migrate_{disable|enable} pairs in the underlying implementation of bpf_obj_free_fields() will be removed by The following patch. Signed-off-by: Hou Tao Link: https://lore.kernel.org/r/20250108010728.207536-8-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov --- diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 2f4ed83a75ae..aa536ecd5d39 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -50,15 +50,16 @@ void bpf_sk_storage_free(struct sock *sk) { struct bpf_local_storage *sk_storage; + migrate_disable(); rcu_read_lock(); sk_storage = rcu_dereference(sk->sk_bpf_storage); - if (!sk_storage) { - rcu_read_unlock(); - return; - } + if (!sk_storage) + goto out; bpf_local_storage_destroy(sk_storage); +out: rcu_read_unlock(); + migrate_enable(); } static void bpf_sk_storage_map_free(struct bpf_map *map)