* [PATCH v2 bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c
@ 2023-08-02 7:39 Alan Maguire
2023-08-02 12:15 ` Yipeng Zou
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Alan Maguire @ 2023-08-02 7:39 UTC (permalink / raw)
To: yhs, ast, andrii
Cc: martin.lau, song, john.fastabend, kpsingh, sdf, haoluo, jolsa,
mykolal, bpf, Alan Maguire, Colm Harrington
commit bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE")
...was backported to stable trees such as 5.15. The problem is that with older
LLVM/clang (14/15) - which is often used for older kernels - we see compilation
failures in BPF selftests now:
In file included from progs/test_cls_redirect_subprogs.c:2:
progs/test_cls_redirect.c:90:2: error: static assertion expression is not an integral constant expression
sizeof(flow_ports_t) !=
^~~~~~~~~~~~~~~~~~~~~~~
progs/test_cls_redirect.c:91:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
offsetofend(struct bpf_sock_tuple, ipv4.dport) -
^
progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend'
(offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
^
tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof'
^
In file included from progs/test_cls_redirect_subprogs.c:2:
progs/test_cls_redirect.c:95:2: error: static assertion expression is not an integral constant expression
sizeof(flow_ports_t) !=
^~~~~~~~~~~~~~~~~~~~~~~
progs/test_cls_redirect.c:96:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
offsetofend(struct bpf_sock_tuple, ipv6.dport) -
^
progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend'
(offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
^
tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof'
^
2 errors generated.
make: *** [Makefile:594: tools/testing/selftests/bpf/test_cls_redirect_subprogs.bpf.o] Error 1
The problem is the new offsetof() does not play nice with static asserts.
Given that the context is a static assert (and CO-RE relocation is not
needed at compile time), offsetof() usage can be replaced by restoring
the original offsetof() definition as __builtin_offsetof().
Fixes: bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE")
Reported-by: Colm Harrington <colm.harrington@oracle.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
---
Changes since v1:
- simplified to restore offsetof() definition in test_cls_redirect.h,
and added explanatory comment (Yonghong)
---
tools/testing/selftests/bpf/progs/test_cls_redirect.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/test_cls_redirect.h b/tools/testing/selftests/bpf/progs/test_cls_redirect.h
index 76eab0aacba0..233b089d1fba 100644
--- a/tools/testing/selftests/bpf/progs/test_cls_redirect.h
+++ b/tools/testing/selftests/bpf/progs/test_cls_redirect.h
@@ -12,6 +12,15 @@
#include <linux/ipv6.h>
#include <linux/udp.h>
+/* offsetof() is used in static asserts, and the libbpf-redefined CO-RE
+ * friendly version breaks compilation for older clang versions <= 15
+ * when invoked in a static assert. Restore original here.
+ */
+#ifdef offsetof
+#undef offsetof
+#define offsetof(type, member) __builtin_offsetof(type, member)
+#endif
+
struct gre_base_hdr {
uint16_t flags;
uint16_t protocol;
--
2.39.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2 bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c
2023-08-02 7:39 [PATCH v2 bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c Alan Maguire
@ 2023-08-02 12:15 ` Yipeng Zou
2023-08-02 14:07 ` Yonghong Song
2023-08-02 21:20 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Yipeng Zou @ 2023-08-02 12:15 UTC (permalink / raw)
To: Alan Maguire, yhs, ast, andrii
Cc: martin.lau, song, john.fastabend, kpsingh, sdf, haoluo, jolsa,
mykolal, bpf, Colm Harrington
在 2023/8/2 15:39, Alan Maguire 写道:
> commit bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE")
>
> ...was backported to stable trees such as 5.15. The problem is that with older
> LLVM/clang (14/15) - which is often used for older kernels - we see compilation
> failures in BPF selftests now:
>
> In file included from progs/test_cls_redirect_subprogs.c:2:
> progs/test_cls_redirect.c:90:2: error: static assertion expression is not an integral constant expression
> sizeof(flow_ports_t) !=
> ^~~~~~~~~~~~~~~~~~~~~~~
> progs/test_cls_redirect.c:91:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
> offsetofend(struct bpf_sock_tuple, ipv4.dport) -
> ^
> progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend'
> (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
> ^
> tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof'
> ^
> In file included from progs/test_cls_redirect_subprogs.c:2:
> progs/test_cls_redirect.c:95:2: error: static assertion expression is not an integral constant expression
> sizeof(flow_ports_t) !=
> ^~~~~~~~~~~~~~~~~~~~~~~
> progs/test_cls_redirect.c:96:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
> offsetofend(struct bpf_sock_tuple, ipv6.dport) -
> ^
> progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend'
> (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
> ^
> tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof'
> ^
> 2 errors generated.
> make: *** [Makefile:594: tools/testing/selftests/bpf/test_cls_redirect_subprogs.bpf.o] Error 1
>
> The problem is the new offsetof() does not play nice with static asserts.
> Given that the context is a static assert (and CO-RE relocation is not
> needed at compile time), offsetof() usage can be replaced by restoring
> the original offsetof() definition as __builtin_offsetof().
>
> Fixes: bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE")
> Reported-by: Colm Harrington <colm.harrington@oracle.com>
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
>
> ---
> Changes since v1:
>
> - simplified to restore offsetof() definition in test_cls_redirect.h,
> and added explanatory comment (Yonghong)
> ---
> tools/testing/selftests/bpf/progs/test_cls_redirect.h | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/progs/test_cls_redirect.h b/tools/testing/selftests/bpf/progs/test_cls_redirect.h
> index 76eab0aacba0..233b089d1fba 100644
> --- a/tools/testing/selftests/bpf/progs/test_cls_redirect.h
> +++ b/tools/testing/selftests/bpf/progs/test_cls_redirect.h
> @@ -12,6 +12,15 @@
> #include <linux/ipv6.h>
> #include <linux/udp.h>
>
> +/* offsetof() is used in static asserts, and the libbpf-redefined CO-RE
> + * friendly version breaks compilation for older clang versions <= 15
> + * when invoked in a static assert. Restore original here.
> + */
> +#ifdef offsetof
> +#undef offsetof
> +#define offsetof(type, member) __builtin_offsetof(type, member)
> +#endif
> +
Oh, I just hit this too, and It's work for me.
Tested-by: Yipeng Zou <zouyipeng@huawei.com>
> struct gre_base_hdr {
> uint16_t flags;
> uint16_t protocol;
--
Regards,
Yipeng Zou
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c
2023-08-02 7:39 [PATCH v2 bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c Alan Maguire
2023-08-02 12:15 ` Yipeng Zou
@ 2023-08-02 14:07 ` Yonghong Song
2023-08-02 21:20 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Yonghong Song @ 2023-08-02 14:07 UTC (permalink / raw)
To: Alan Maguire, yhs, ast, andrii
Cc: martin.lau, song, john.fastabend, kpsingh, sdf, haoluo, jolsa,
mykolal, bpf, Colm Harrington
On 8/2/23 12:39 AM, Alan Maguire wrote:
> commit bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE")
>
> ...was backported to stable trees such as 5.15. The problem is that with older
> LLVM/clang (14/15) - which is often used for older kernels - we see compilation
> failures in BPF selftests now:
>
> In file included from progs/test_cls_redirect_subprogs.c:2:
> progs/test_cls_redirect.c:90:2: error: static assertion expression is not an integral constant expression
> sizeof(flow_ports_t) !=
> ^~~~~~~~~~~~~~~~~~~~~~~
> progs/test_cls_redirect.c:91:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
> offsetofend(struct bpf_sock_tuple, ipv4.dport) -
> ^
> progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend'
> (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
> ^
> tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof'
> ^
> In file included from progs/test_cls_redirect_subprogs.c:2:
> progs/test_cls_redirect.c:95:2: error: static assertion expression is not an integral constant expression
> sizeof(flow_ports_t) !=
> ^~~~~~~~~~~~~~~~~~~~~~~
> progs/test_cls_redirect.c:96:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
> offsetofend(struct bpf_sock_tuple, ipv6.dport) -
> ^
> progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend'
> (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
> ^
> tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof'
> ^
> 2 errors generated.
> make: *** [Makefile:594: tools/testing/selftests/bpf/test_cls_redirect_subprogs.bpf.o] Error 1
>
> The problem is the new offsetof() does not play nice with static asserts.
> Given that the context is a static assert (and CO-RE relocation is not
> needed at compile time), offsetof() usage can be replaced by restoring
> the original offsetof() definition as __builtin_offsetof().
>
> Fixes: bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE")
> Reported-by: Colm Harrington <colm.harrington@oracle.com>
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c
2023-08-02 7:39 [PATCH v2 bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c Alan Maguire
2023-08-02 12:15 ` Yipeng Zou
2023-08-02 14:07 ` Yonghong Song
@ 2023-08-02 21:20 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2023-08-02 21:20 UTC (permalink / raw)
To: Alan Maguire
Cc: yhs, ast, andrii, martin.lau, song, john.fastabend, kpsingh, sdf,
haoluo, jolsa, mykolal, bpf, colm.harrington
Hello:
This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:
On Wed, 2 Aug 2023 08:39:06 +0100 you wrote:
> commit bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE")
>
> ...was backported to stable trees such as 5.15. The problem is that with older
> LLVM/clang (14/15) - which is often used for older kernels - we see compilation
> failures in BPF selftests now:
>
> In file included from progs/test_cls_redirect_subprogs.c:2:
> progs/test_cls_redirect.c:90:2: error: static assertion expression is not an integral constant expression
> sizeof(flow_ports_t) !=
> ^~~~~~~~~~~~~~~~~~~~~~~
> progs/test_cls_redirect.c:91:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
> offsetofend(struct bpf_sock_tuple, ipv4.dport) -
> ^
> progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend'
> (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
> ^
> tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof'
> ^
> In file included from progs/test_cls_redirect_subprogs.c:2:
> progs/test_cls_redirect.c:95:2: error: static assertion expression is not an integral constant expression
> sizeof(flow_ports_t) !=
> ^~~~~~~~~~~~~~~~~~~~~~~
> progs/test_cls_redirect.c:96:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression
> offsetofend(struct bpf_sock_tuple, ipv6.dport) -
> ^
> progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend'
> (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER)))
> ^
> tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof'
> ^
> 2 errors generated.
> make: *** [Makefile:594: tools/testing/selftests/bpf/test_cls_redirect_subprogs.bpf.o] Error 1
>
> [...]
Here is the summary with links:
- [v2,bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c
https://git.kernel.org/bpf/bpf-next/c/416c6d01244e
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
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2023-08-02 7:39 [PATCH v2 bpf] selftests/bpf: fix static assert compilation issue for test_cls_*.c Alan Maguire
2023-08-02 12:15 ` Yipeng Zou
2023-08-02 14:07 ` Yonghong Song
2023-08-02 21:20 ` patchwork-bot+netdevbpf
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