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From: Jakub Sitnicki <>
To: John Fastabend <>,
	Daniel Borkmann <>,
	Lorenz Bauer <>,
	Alexei Starovoitov <>,
	Andrii Nakryiko <>
Subject: [PATCH bpf] bpf, sockmap, udp: sk_prot needs inuse_idx set for proc stats
Date: Tue, 13 Jul 2021 09:44:01 +0200	[thread overview]
Message-ID: <> (raw)

Proc socket stats use sk_prot->inuse_idx value to record inuse sock stats.
We currently do not set this correctly from sockmap side. The result is
reading sock stats '/proc/net/sockstat' gives incorrect values. The
socket counter is incremented correctly, but because we don't set the
counter correctly when we replace sk_prot we may omit the decrement.

To get the correct inuse_idx value move the core_initcall that initializes
the udp proto handlers to late_initcall. This way it is initialized after
UDP has the chance to assign the inuse_idx value from the register protocol

Fixes: 5e21bb4e8125 ("bpf, test: fix NULL pointer dereference on invalid expected_attach_type")
Signed-off-by: Jakub Sitnicki <>

Missing bit from John's fix [1].


 net/ipv4/udp_bpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/udp_bpf.c b/net/ipv4/udp_bpf.c
index 45b8782aec0c..9f5a5cdc38e6 100644
--- a/net/ipv4/udp_bpf.c
+++ b/net/ipv4/udp_bpf.c
@@ -134,7 +134,7 @@ static int __init udp_bpf_v4_build_proto(void)
 	udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
 	return 0;
 int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)

             reply	other threads:[~2021-07-13  7:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-13  7:44 Jakub Sitnicki [this message]
2021-07-14  0:28 ` John Fastabend
2021-07-14  0:51 ` Cong Wang
2021-07-14 15:56   ` Jakub Sitnicki

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