diff options
Diffstat (limited to 'net/ipv4/bpf_tcp_ca.c')
| -rw-r--r-- | net/ipv4/bpf_tcp_ca.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c index 9deed2244c2d..2a71dc81562f 100644 --- a/net/ipv4/bpf_tcp_ca.c +++ b/net/ipv4/bpf_tcp_ca.c @@ -340,6 +340,22 @@ static struct bpf_struct_ops bpf_tcp_congestion_ops = { .validate = bpf_tcp_ca_validate, .name = "tcp_congestion_ops", .cfi_stubs = &__bpf_ops_tcp_congestion_ops, + /* The struct_ops's function may switch to another struct_ops. + * + * For example, bpf_tcp_cc_x->init() may switch to + * another tcp_cc_y by calling + * setsockopt(TCP_CONGESTION, "tcp_cc_y"). + * During the switch, bpf_struct_ops_put(tcp_cc_x) is called + * and its refcount may reach 0 which then free its + * trampoline image while tcp_cc_x is still running. + * + * A vanilla rcu gp is to wait for all bpf-tcp-cc prog + * to finish. bpf-tcp-cc prog is non sleepable. + * A rcu_tasks gp is to wait for the last few insn + * in the tramopline image to finish before releasing + * the trampoline image. + */ + .free_after_tasks_rcu_gp = true, .owner = THIS_MODULE, }; |