[PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

Subsystems: bpf [general] (safe dynamic programs and tools), the rest

STALE2133d

8 messages, 3 authors, 2020-10-01 · open the first message on its own page

[PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

From: Yonghong Song <hidden>
Date: 2020-09-30 16:41:21

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, omit the above two types for BTF_SOCK_TYPE_xxx
macro if CONFIG_INET is not defined.

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 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..d9a1e18d0921 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -102,24 +102,36 @@ 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)
 
+#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)
+
+#ifdef CONFIG_INET
+#define BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TW_TYPE_xxx
+#else
+#define BTF_SOCK_TYPE_xxx	__BTF_SOCK_TYPE_xxx
+#endif
+
 enum {
 #define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TW_TYPE_xxx
 #undef BTF_SOCK_TYPE
 MAX_BTF_SOCK_TYPE,
 };
-- 
2.24.1

Re: [PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

From: Andrii Nakryiko <hidden>
Date: 2020-09-30 18:40:50

On Wed, Sep 30, 2020 at 9:41 AM Yonghong Song [off-list ref] wrote:
quoted hunk
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, omit the above two types for BTF_SOCK_TYPE_xxx
macro if CONFIG_INET is not defined.

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 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..d9a1e18d0921 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -102,24 +102,36 @@ 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)

+#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)
+
+#ifdef CONFIG_INET
+#define BTF_SOCK_TYPE_xxx                                              \
+       __BTF_SOCK_TYPE_xxx                                             \
+       __BTF_SOCK_TW_TYPE_xxx
+#else
+#define BTF_SOCK_TYPE_xxx      __BTF_SOCK_TYPE_xxx
+#endif
+
 enum {
 #define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TW_TYPE_xxx
Why BTF_SOCK_TYPE_xxx doesn't still work here after the above changes?
 #undef BTF_SOCK_TYPE
 MAX_BTF_SOCK_TYPE,
 };
--
2.24.1

Re: [PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

From: Yonghong Song <hidden>
Date: 2020-09-30 19:25:22


On 9/30/20 11:40 AM, Andrii Nakryiko wrote:
On Wed, Sep 30, 2020 at 9:41 AM Yonghong Song [off-list ref] wrote:
quoted
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, omit the above two types for BTF_SOCK_TYPE_xxx
macro if CONFIG_INET is not defined.

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 ++++++++++++++++----
  1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..d9a1e18d0921 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -102,24 +102,36 @@ 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)

+#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)
+
+#ifdef CONFIG_INET
+#define BTF_SOCK_TYPE_xxx                                              \
+       __BTF_SOCK_TYPE_xxx                                             \
+       __BTF_SOCK_TW_TYPE_xxx
+#else
+#define BTF_SOCK_TYPE_xxx      __BTF_SOCK_TYPE_xxx
+#endif
+
  enum {
  #define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TW_TYPE_xxx
Why BTF_SOCK_TYPE_xxx doesn't still work here after the above changes?
The macro, e.g., BTF_SOCK_TYPE_TCP_TW, still needed to be defined as
it is used to get the location for btf_id.

const struct bpf_func_proto bpf_skc_to_tcp_timewait_sock_proto = {
         .func                   = bpf_skc_to_tcp_timewait_sock,
         .gpl_only               = false,
         .ret_type               = RET_PTR_TO_BTF_ID_OR_NULL,
         .arg1_type              = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
         .ret_btf_id             = &btf_sock_ids[BTF_SOCK_TYPE_TCP_TW],
};

If CONFIG_INET is not defined, bpf_sock_ids[BTF_SOCK_TYPE_TCP_TW]
will be 0.
quoted
  #undef BTF_SOCK_TYPE
  MAX_BTF_SOCK_TYPE,
  };
--
2.24.1

Re: [PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

From: Andrii Nakryiko <hidden>
Date: 2020-09-30 19:44:33

On Wed, Sep 30, 2020 at 12:25 PM Yonghong Song [off-list ref] wrote:


On 9/30/20 11:40 AM, Andrii Nakryiko wrote:
quoted
On Wed, Sep 30, 2020 at 9:41 AM Yonghong Song [off-list ref] wrote:
quoted
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, omit the above two types for BTF_SOCK_TYPE_xxx
macro if CONFIG_INET is not defined.

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 ++++++++++++++++----
  1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..d9a1e18d0921 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -102,24 +102,36 @@ 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)

+#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)
+
+#ifdef CONFIG_INET
+#define BTF_SOCK_TYPE_xxx                                              \
+       __BTF_SOCK_TYPE_xxx                                             \
+       __BTF_SOCK_TW_TYPE_xxx
+#else
+#define BTF_SOCK_TYPE_xxx      __BTF_SOCK_TYPE_xxx
+#endif
+
  enum {
  #define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TW_TYPE_xxx
Why BTF_SOCK_TYPE_xxx doesn't still work here after the above changes?
The macro, e.g., BTF_SOCK_TYPE_TCP_TW, still needed to be defined as
it is used to get the location for btf_id.
Ah, right, so you want those here unconditionally, even if CONFIG_INET
is not defined. Missed that. Might be worth leaving a short comment.

Otherwise LGTM.

Acked-by: Andrii Nakryiko <redacted>
const struct bpf_func_proto bpf_skc_to_tcp_timewait_sock_proto = {
         .func                   = bpf_skc_to_tcp_timewait_sock,
         .gpl_only               = false,
         .ret_type               = RET_PTR_TO_BTF_ID_OR_NULL,
         .arg1_type              = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
         .ret_btf_id             = &btf_sock_ids[BTF_SOCK_TYPE_TCP_TW],
};

If CONFIG_INET is not defined, bpf_sock_ids[BTF_SOCK_TYPE_TCP_TW]
will be 0.
quoted
quoted
  #undef BTF_SOCK_TYPE
  MAX_BTF_SOCK_TYPE,
  };
--
2.24.1

Re: [PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

From: Martin KaFai Lau <hidden>
Date: 2020-09-30 20:59:15

On Wed, Sep 30, 2020 at 09:41:09AM -0700, Yonghong Song wrote:
quoted hunk
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, omit the above two types for BTF_SOCK_TYPE_xxx
macro if CONFIG_INET is not defined.

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 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..d9a1e18d0921 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -102,24 +102,36 @@ 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)
 
+#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)
+
+#ifdef CONFIG_INET
+#define BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TW_TYPE_xxx
+#else
+#define BTF_SOCK_TYPE_xxx	__BTF_SOCK_TYPE_xxx
BTF_SOCK_TYPE_xxx is used in BTF_ID_LIST_GLOBAL(btf_sock_ids) in filter.c
which does not include BTF_SOCK_TYPE_TCP_TW.
However, btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] is still used
in bpf_skc_to_tcp_timewait_sock_proto.
+#endif
+
 enum {
 #define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TW_TYPE_xxx
BTF_SOCK_TYPE_TCP_TW is at the end of this enum.

Would btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] always be 0?
 #undef BTF_SOCK_TYPE
 MAX_BTF_SOCK_TYPE,
 };
-- 
2.24.1

Re: [PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

From: Yonghong Song <hidden>
Date: 2020-09-30 22:50:34


On 9/30/20 1:58 PM, Martin KaFai Lau wrote:
On Wed, Sep 30, 2020 at 09:41:09AM -0700, Yonghong Song wrote:
quoted
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, omit the above two types for BTF_SOCK_TYPE_xxx
macro if CONFIG_INET is not defined.

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 ++++++++++++++++----
  1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..d9a1e18d0921 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -102,24 +102,36 @@ 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)
  
+#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)
+
+#ifdef CONFIG_INET
+#define BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TW_TYPE_xxx
+#else
+#define BTF_SOCK_TYPE_xxx	__BTF_SOCK_TYPE_xxx
BTF_SOCK_TYPE_xxx is used in BTF_ID_LIST_GLOBAL(btf_sock_ids) in filter.c
which does not include BTF_SOCK_TYPE_TCP_TW.
However, btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] is still used
in bpf_skc_to_tcp_timewait_sock_proto.
quoted
+#endif
+
  enum {
  #define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TW_TYPE_xxx
BTF_SOCK_TYPE_TCP_TW is at the end of this enum.

Would btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] always be 0?
No. If CONFIG_INET is y, the above BTF_SOCK_TYPE_xxx contains
   __BTF_SOCK_TW_TYPE_xxx
and
   btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] will be calculated properly.

But if CONFIG_INET is n, then BTF_SOCK_TYPE_xxx will not contain
    __BTF_SOCK_TW_TYPE_xxx
so btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] will have default value 0
as btf_sock_ids is a global.

Will send v2 to add some comments to make it easy to understand.
quoted
  #undef BTF_SOCK_TYPE
  MAX_BTF_SOCK_TYPE,
  };
-- 
2.24.1

Re: [PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

From: Martin KaFai Lau <hidden>
Date: 2020-09-30 23:00:13

On Wed, Sep 30, 2020 at 03:50:10PM -0700, Yonghong Song wrote:

On 9/30/20 1:58 PM, Martin KaFai Lau wrote:
quoted
On Wed, Sep 30, 2020 at 09:41:09AM -0700, Yonghong Song wrote:
quoted
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, omit the above two types for BTF_SOCK_TYPE_xxx
macro if CONFIG_INET is not defined.

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 ++++++++++++++++----
  1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..d9a1e18d0921 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -102,24 +102,36 @@ 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)
+#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)
+
+#ifdef CONFIG_INET
+#define BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TW_TYPE_xxx
+#else
+#define BTF_SOCK_TYPE_xxx	__BTF_SOCK_TYPE_xxx
BTF_SOCK_TYPE_xxx is used in BTF_ID_LIST_GLOBAL(btf_sock_ids) in filter.c
which does not include BTF_SOCK_TYPE_TCP_TW.
However, btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] is still used
in bpf_skc_to_tcp_timewait_sock_proto.
quoted
+#endif
+
  enum {
  #define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TW_TYPE_xxx
BTF_SOCK_TYPE_TCP_TW is at the end of this enum.

Would btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] always be 0?
No. If CONFIG_INET is y, the above BTF_SOCK_TYPE_xxx contains
  __BTF_SOCK_TW_TYPE_xxx
and
  btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] will be calculated properly.

But if CONFIG_INET is n, then BTF_SOCK_TYPE_xxx will not contain
   __BTF_SOCK_TW_TYPE_xxx
so btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] will have default value 0
as btf_sock_ids is a global.
I could be missing something here.
Why btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] must be 0?
How does BTF_ID_LIST_GLOBAL() know there is a
btf_sock_ids[BTF_SOCK_TYPE_TCP_TW]?
I would expect at least BTF_ID_UNUSED is required.
Otherwise, the value will be whatever follow the last
btf_sock_ids[BTF_SOCK_TYPE_UDP6].
Will send v2 to add some comments to make it easy to understand.
quoted
quoted
  #undef BTF_SOCK_TYPE
  MAX_BTF_SOCK_TYPE,
  };
-- 
2.24.1

Re: [PATCH bpf] bpf: fix "unresolved symbol" build error with resolve_btfids

From: Yonghong Song <hidden>
Date: 2020-10-01 01:00:28


On 9/30/20 3:59 PM, Martin KaFai Lau wrote:
On Wed, Sep 30, 2020 at 03:50:10PM -0700, Yonghong Song wrote:
quoted

On 9/30/20 1:58 PM, Martin KaFai Lau wrote:
quoted
On Wed, Sep 30, 2020 at 09:41:09AM -0700, Yonghong Song wrote:
quoted
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, omit the above two types for BTF_SOCK_TYPE_xxx
macro if CONFIG_INET is not defined.

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 ++++++++++++++++----
   1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 4867d549e3c1..d9a1e18d0921 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -102,24 +102,36 @@ 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)
+#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)
+
+#ifdef CONFIG_INET
+#define BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TYPE_xxx						\
+	__BTF_SOCK_TW_TYPE_xxx
+#else
+#define BTF_SOCK_TYPE_xxx	__BTF_SOCK_TYPE_xxx
BTF_SOCK_TYPE_xxx is used in BTF_ID_LIST_GLOBAL(btf_sock_ids) in filter.c
which does not include BTF_SOCK_TYPE_TCP_TW.
However, btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] is still used
in bpf_skc_to_tcp_timewait_sock_proto.
quoted
+#endif
+
   enum {
   #define BTF_SOCK_TYPE(name, str) name,
-BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TYPE_xxx
+__BTF_SOCK_TW_TYPE_xxx
BTF_SOCK_TYPE_TCP_TW is at the end of this enum.

Would btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] always be 0?
No. If CONFIG_INET is y, the above BTF_SOCK_TYPE_xxx contains
   __BTF_SOCK_TW_TYPE_xxx
and
   btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] will be calculated properly.

But if CONFIG_INET is n, then BTF_SOCK_TYPE_xxx will not contain
    __BTF_SOCK_TW_TYPE_xxx
so btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] will have default value 0
as btf_sock_ids is a global.
I could be missing something here.
Why btf_sock_ids[BTF_SOCK_TYPE_TCP_TW] must be 0?
How does BTF_ID_LIST_GLOBAL() know there is a
btf_sock_ids[BTF_SOCK_TYPE_TCP_TW]?
I would expect at least BTF_ID_UNUSED is required.
Otherwise, the value will be whatever follow the last
btf_sock_ids[BTF_SOCK_TYPE_UDP6].
Right, I realized later on when I prepare v2. Will send patch v2 shortly.
quoted
Will send v2 to add some comments to make it easy to understand.
quoted
quoted
   #undef BTF_SOCK_TYPE
   MAX_BTF_SOCK_TYPE,
   };
-- 
2.24.1
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