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From: Yonghong Song <yhs@fb.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Andrii Nakryiko <andriin@fb.com>, bpf <bpf@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	Alexei Starovoitov <ast@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 1/7] libbpf: disable -Wswitch-enum compiler warning
Date: Tue, 18 Aug 2020 22:44:26 -0700	[thread overview]
Message-ID: <d69666c9-9c63-386f-130c-e30aba92e7c1@fb.com> (raw)
In-Reply-To: <CAEf4BzaTWVhymaGuSHHHL8+TCbP=qRFc+YvG+ZMYMNTEg-vA-A@mail.gmail.com>



On 8/18/20 6:39 PM, Andrii Nakryiko wrote:
> On Tue, Aug 18, 2020 at 6:23 PM Yonghong Song <yhs@fb.com> wrote:
>>
>>
>>
>> On 8/18/20 2:33 PM, Andrii Nakryiko wrote:
>>> That compilation warning is more annoying, than helpful.
>>
>> Curious which compiler and which version caused this issue?
>> I did not hit with gcc 8.2 or latest clang in my environment.
>>
> 
> Strange, I just tried on bpf-next, removed -Wno-switch-enum and got
> tons of errors:
> 
> libbpf.c: In function ‘bpf_object__sanitize_prog’:
> libbpf.c:5560:3: error: enumeration value ‘BPF_FUNC_unspec’ not
> handled in switch [-Werror=switch-enum]
>     switch (func_id) {
>     ^~~~~~
> libbpf.c:5560:3: error: enumeration value ‘BPF_FUNC_map_lookup_elem’
> not handled in switch [-Werror=switch-enum]
> libbpf.c:5560:3: error: enumeration value ‘BPF_FUNC_map_update_elem’
> not handled in switch [-Werror=switch-enum]
> ... and many more ...

Okay I can reproduce now with latest bpf-next but not bpf.
Now I understand why you introduced this additional option.
The issue is introduced by the above code in Patch #4. To compile
patch #4, you need -Wno-switch-enum.

> 
> My compiler:
> 
> $ cc --version
> cc (GCC) 8.2.1 20180801 (Red Hat 8.2.1-2)
> 
> 
>>>
>>> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
>>> ---
>>>    tools/lib/bpf/Makefile | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
>>> index bf8ed134cb8a..95c946e94ca5 100644
>>> --- a/tools/lib/bpf/Makefile
>>> +++ b/tools/lib/bpf/Makefile
>>> @@ -107,7 +107,7 @@ ifeq ($(feature-reallocarray), 0)
>>>    endif
>>>
>>>    # Append required CFLAGS
>>> -override CFLAGS += $(EXTRA_WARNINGS)
>>> +override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum
>>>    override CFLAGS += -Werror -Wall
>>>    override CFLAGS += -fPIC
>>>    override CFLAGS += $(INCLUDES)
>>>

  reply	other threads:[~2020-08-19  5:44 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-18 21:33 [PATCH bpf-next 0/7] libbpf feature probing and sanitization improvements Andrii Nakryiko
2020-08-18 21:33 ` [PATCH bpf-next 1/7] libbpf: disable -Wswitch-enum compiler warning Andrii Nakryiko
2020-08-19  1:23   ` Yonghong Song
2020-08-19  1:39     ` Andrii Nakryiko
2020-08-19  5:44       ` Yonghong Song [this message]
2020-08-18 21:33 ` [PATCH bpf-next 2/7] libbpf: make kernel feature probing lazy Andrii Nakryiko
2020-08-18 21:33 ` [PATCH bpf-next 3/7] libbpf: factor out common logic of testing and closing FD Andrii Nakryiko
2020-08-18 21:33 ` [PATCH bpf-next 4/7] libbpf: sanitize BPF program code for bpf_probe_read_{kernel,user}[_str] Andrii Nakryiko
2020-08-19  1:42   ` Yonghong Song
2020-08-19 20:11     ` Andrii Nakryiko
2020-08-19 20:15       ` Alexei Starovoitov
2020-08-19 20:23         ` Andrii Nakryiko
2020-08-18 21:33 ` [PATCH bpf-next 5/7] selftests/bpf: fix test_vmlinux test to use bpf_probe_read_user() Andrii Nakryiko
2020-08-18 21:33 ` [PATCH bpf-next 6/7] libbpf: switch tracing and CO-RE helper macros to bpf_probe_read_kernel() Andrii Nakryiko
2020-08-18 21:33 ` [PATCH bpf-next 7/7] libbpf: detect minimal BTF support and skip BTF loading, if missing Andrii Nakryiko
2020-08-19  0:24 ` [PATCH bpf-next 0/7] libbpf feature probing and sanitization improvements Alexei Starovoitov

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