[PATCH bpf v2] bpf: fix "unresolved symbol" build error with resolve_btfids
DORMANTno replies
From: Yonghong Song <hidden>
Date: 2020-10-01 01:02:32
Also in:
bpf
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
Michal reported a build failure likes below:
BTFIDS vmlinux
FAILED unresolved symbol tcp_timewait_sock
make[1]: *** [/.../linux-5.9-rc7/Makefile:1176: vmlinux] Error 255
This error can be triggered when config has CONFIG_NET enabled
but CONFIG_INET disabled. In this case, there is no user of
structs inet_timewait_sock and tcp_timewait_sock and hence vmlinux BTF
types are not generated for these two structures.
To fix the problem, for two timewait structures, if CONFIG_INET=n,
use BTF_ID_UNUSED instead of BTF_ID to skip btf id generation
in resolve_btfids.
Fixes: fce557bcef11 ("bpf: Make btf_sock_ids global")
Reported-by: Michal Kubecek <redacted>
Signed-off-by: Yonghong Song <redacted>
---
include/linux/btf_ids.h | 20 +++++++++++++++++---
net/core/filter.c | 1 +
2 files changed, 18 insertions(+), 3 deletions(-)
Changelog:
v1 -> v2:
. For unsupported socket times, using BTF_ID_UNUSED to
keep the id as 0. (Martin)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..9c49bf89a9a7 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h@@ -102,23 +102,37 @@ asm( \ * skc_to_*_sock() helpers. All these sockets should have * sock_common as the first argument in its memory layout. */ -#define BTF_SOCK_TYPE_xxx \ + +#define __BTF_SOCK_TYPE_xxx \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET, inet_sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_CONN, inet_connection_sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_REQ, inet_request_sock) \ - BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, inet_timewait_sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_REQ, request_sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK, sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK_COMMON, sock_common) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP, tcp_sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_REQ, tcp_request_sock) \ - BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, tcp_timewait_sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, tcp6_sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, udp_sock) \ BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock) +#ifdef CONFIG_INET +#define __BTF_SOCK_TW_TYPE_xxx \ + BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, inet_timewait_sock) \ + BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, tcp_timewait_sock) +#else +#define __BTF_SOCK_TW_TYPE_xxx \ + BTF_SOCK_TYPE_UNUSED(BTF_SOCK_TYPE_INET_TW) \ + BTF_SOCK_TYPE_UNUSED(BTF_SOCK_TYPE_TCP_TW) +#endif + +#define BTF_SOCK_TYPE_xxx \ + __BTF_SOCK_TYPE_xxx \ + __BTF_SOCK_TW_TYPE_xxx + enum { #define BTF_SOCK_TYPE(name, str) name, +#define BTF_SOCK_TYPE_UNUSED(name) name, BTF_SOCK_TYPE_xxx #undef BTF_SOCK_TYPE MAX_BTF_SOCK_TYPE,
diff --git a/net/core/filter.c b/net/core/filter.c
index 21eaf3b182f2..396fe928e202 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -9500,6 +9500,7 @@ void bpf_prog_change_xdp(struct bpf_prog *prev_prog, struct bpf_prog *prog) #ifdef CONFIG_DEBUG_INFO_BTF BTF_ID_LIST_GLOBAL(btf_sock_ids) #define BTF_SOCK_TYPE(name, type) BTF_ID(struct, type) +#define BTF_SOCK_TYPE_UNUSED(name) BTF_ID_UNUSED BTF_SOCK_TYPE_xxx #undef BTF_SOCK_TYPE #else
--
2.24.1