From: Hou Tao <houtao1@xxxxxxxxxx>
bpf_sk_storage_clone() will call bpf_selem_free() to free the clone
element when the allocation of new sock storage fails. bpf_selem_free()
will call check_and_free_fields() to free the special fields in the
element. Since the allocated element is not visible to bpf syscall or
bpf program when bpf_local_storage_alloc() fails, these special fields
in the element must be all zero when invoking bpf_selem_free().
To be uniform with other callers of bpf_selem_free(), disabling
migration when cloning sock storage. Adding migrate_{disable|enable}
pair also benefits the potential switching from kzalloc to bpf memory
allocator for sock storage.
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
net/core/bpf_sk_storage.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index aa536ecd5d390..7d41cde1bcca6 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -161,6 +161,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
RCU_INIT_POINTER(newsk->sk_bpf_storage, NULL);
+ migrate_disable();
rcu_read_lock();
sk_storage = rcu_dereference(sk->sk_bpf_storage);
@@ -213,6 +214,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
out:
rcu_read_unlock();
+ migrate_enable();
/* In case of an error, don't free anything explicitly here, the
* caller is responsible to call bpf_sk_storage_free.
--
2.29.2
