On Tue, Jan 26, 2021 at 10:36 AM Florent Revest <[email protected]> wrote: > > When migrating from the bpf.h's to the vmlinux.h's definition of struct > bps_sock, an interesting LLVM behavior happened. LLVM started producing > two fetches of ctx->sk in the sockops program this means that the > verifier could not keep track of the NULL-check on ctx->sk. Therefore, > we need to extract ctx->sk in a variable before checking and > dereferencing it. > > Acked-by: KP Singh <[email protected]> > Signed-off-by: Florent Revest <[email protected]> > ---
Acked-by: Andrii Nakryiko <[email protected]> > .../testing/selftests/bpf/progs/socket_cookie_prog.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c > b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c > index 81e84be6f86d..fbd5eaf39720 100644 > --- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c > +++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c > @@ -1,12 +1,13 @@ > // SPDX-License-Identifier: GPL-2.0 > // Copyright (c) 2018 Facebook > > -#include <linux/bpf.h> > -#include <sys/socket.h> > +#include "vmlinux.h" > > #include <bpf/bpf_helpers.h> > #include <bpf/bpf_endian.h> > > +#define AF_INET6 10 > + > struct socket_cookie { > __u64 cookie_key; > __u32 cookie_value; > @@ -41,7 +42,7 @@ int set_cookie(struct bpf_sock_addr *ctx) > SEC("sockops") > int update_cookie(struct bpf_sock_ops *ctx) > { > - struct bpf_sock *sk; > + struct bpf_sock *sk = ctx->sk; > struct socket_cookie *p; > > if (ctx->family != AF_INET6) > @@ -50,10 +51,10 @@ int update_cookie(struct bpf_sock_ops *ctx) > if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB) > return 1; > > - if (!ctx->sk) > + if (!sk) > return 1; > > - p = bpf_sk_storage_get(&socket_cookies, ctx->sk, 0, 0); > + p = bpf_sk_storage_get(&socket_cookies, sk, 0, 0); > if (!p) > return 1; > > -- > 2.30.0.280.ga3ce27912f-goog >
