[PATCH bpf v2 1/2] bpf: Extract shared reqsk-to-listener upgrade
From: Michal Luczaj <hidden>
Date: 2026-08-03 09:01:51
Also in:
bpf, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
__bpf_sk_lookup() and bpf_sk_lookup() duplicate the same sk_to_full_sk() reqsk-to-listener upgrade. Extract it into a helper. Leave the currently unreachable WARN_ONCE as a defensive assert. No functional change. Signed-off-by: Michal Luczaj <redacted> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> --- net/core/filter.c | 58 +++++++++++++++++++++++++------------------------------ 1 file changed, 26 insertions(+), 32 deletions(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index 11bb0d236822..fede810ef37f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -7079,6 +7079,28 @@ __bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, return sk; } +static struct sock * +bpf_sk_lookup_full_sk(struct sock *sk) +{ + struct sock *sk2 = sk_to_full_sk(sk); + + /* + * sk_to_full_sk() may return sk->rsk_listener, make sure the original + * sk sock refcnt is decremented to prevent a request_sock leak. + */ + if (sk2 != sk) { + sock_gen_put(sk); + /* Ensure there is no need to bump sk2 refcnt. */ + if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) { + WARN_ONCE(1, "Found non-RCU, unreferenced socket!"); + return NULL; + } + sk = sk2; + } + + return sk; +} + static struct sock * __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,
@@ -7088,22 +7110,8 @@ __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, ifindex, proto, netns_id, flags, sdif); - if (sk) { - struct sock *sk2 = sk_to_full_sk(sk); - - /* sk_to_full_sk() may return (sk)->rsk_listener, so make sure the original sk - * sock refcnt is decremented to prevent a request_sock leak. - */ - if (sk2 != sk) { - sock_gen_put(sk); - /* Ensure there is no need to bump sk2 refcnt */ - if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) { - WARN_ONCE(1, "Found non-RCU, unreferenced socket!"); - return NULL; - } - sk = sk2; - } - } + if (sk) + sk = bpf_sk_lookup_full_sk(sk); return sk; }
@@ -7134,22 +7142,8 @@ bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, struct sock *sk = bpf_skc_lookup(skb, tuple, len, proto, netns_id, flags); - if (sk) { - struct sock *sk2 = sk_to_full_sk(sk); - - /* sk_to_full_sk() may return (sk)->rsk_listener, so make sure the original sk - * sock refcnt is decremented to prevent a request_sock leak. - */ - if (sk2 != sk) { - sock_gen_put(sk); - /* Ensure there is no need to bump sk2 refcnt */ - if (unlikely(sk2 && !sock_flag(sk2, SOCK_RCU_FREE))) { - WARN_ONCE(1, "Found non-RCU, unreferenced socket!"); - return NULL; - } - sk = sk2; - } - } + if (sk) + sk = bpf_sk_lookup_full_sk(sk); return sk; }
--
2.55.0