From: Hengqi Chen <hengqi.chen@gmail.com>
To: Martin KaFai Lau <kafai@fb.com>
Cc: bpf <bpf@vger.kernel.org>,
alan.maguire@oracle.com, Yonghong Song <yhs@fb.com>
Subject: Re: BUG: Ksnoop tool failed to pass the BPF verifier with recent kernel changes
Date: Sat, 16 Oct 2021 17:57:43 +0800 [thread overview]
Message-ID: <da0a8a77-eb71-57c3-35b9-f1dcaeaa560d@gmail.com> (raw)
In-Reply-To: <20211015193010.22frp6eat3wz54hq@kafai-mbp.dhcp.thefacebook.com>
On 2021/10/16 3:30 AM, Martin KaFai Lau wrote:
> On Thu, Oct 14, 2021 at 12:35:42AM +0800, Hengqi Chen wrote:
>> Hi, BPF community,
>>
>>
>> I would like to report a possible bug in bpf-next,
>> hope I don't make any stupid mistake. Here is the details:
>>
>> I have two VMs:
>>
>> One has the kernel built against the following commit:
>>
>> 0693b27644f04852e46f7f034e3143992b658869 (bpf-next)
>>
>> The ksnoop tool (from BCC repo) works well on this VM.
>>
>>
>> Another has the kernel built against the following commit:
>>
>> 5319255b8df9271474bc9027cabf82253934f28d (bpf-next)
>>
>> On this VM, the ksnoop tool failed with the following message:
> I see the error in both mentioned bpf-next commits above.
> I use the latest llvm and bcc from github.
>
> Can you confirm which llvm version (or llvm git commit) you are using
> in both the good and the bad case?
>
Indeed, this could be the problem of LLVM, not the kernel.
The following is the version info of my environment:
The good one:
llvm-config-14 --version
14.0.0
clang -v
Ubuntu clang version 14.0.0-++20210915052613+c78ed20784ee-1~exp1~20210915153417.547
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/9
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/9
Candidate multilib: .;@m64
Selected multilib: .;@m64
The bad one:
llvm-config-14 --version
14.0.0
clang -v
Ubuntu clang version 14.0.0-++20211008104411+f4145c074cb8-1~exp1~20211008085218.709
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/10
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/9
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/11
Candidate multilib: .;@m64
Selected multilib: .;@m64
next prev parent reply other threads:[~2021-10-16 9:57 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-13 16:35 BUG: Ksnoop tool failed to pass the BPF verifier with recent kernel changes Hengqi Chen
2021-10-15 19:30 ` Martin KaFai Lau
2021-10-16 9:57 ` Hengqi Chen [this message]
2021-10-18 13:53 ` Alan Maguire
2021-10-19 3:59 ` Yonghong Song
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