From: Martin KaFai Lau <martin.lau@linux.dev>
To: Grant Seltzer Richman <grantseltzer@gmail.com>
Cc: andrii@kernel.org, kpsingh@kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH v2 bpf-next] Add support for tracing programs in BPF_PROG_RUN
Date: Mon, 6 Feb 2023 12:37:14 -0800 [thread overview]
Message-ID: <f2afdc22-a9c1-eaad-fab4-2ff61b409282@linux.dev> (raw)
In-Reply-To: <CAO658oVRQTL8HfKFJ3X8zjYRLJCQWROjzyOcXeP=uVRML1UYOw@mail.gmail.com>
On 2/5/23 9:29 AM, Grant Seltzer Richman wrote:
> On Sat, Feb 4, 2023 at 1:58 AM Martin KaFai Lau <martin.lau@linux.dev> wrote:
>>
>> On 2/3/23 10:28 AM, Grant Seltzer wrote:
>>> This patch changes the behavior of how BPF_PROG_RUN treats tracing
>>> (fentry/fexit) programs. Previously only a return value is injected
>>> but the actual program was not run.
>>
>> hmm... I don't understand this. The actual program is run by attaching to the
>> bpf_fentry_test{1,2,3...}. eg. The test in fentry_test.c
>
> I'm not sure what you mean. Are you saying in order to use the
> BPF_PROG_RUN bpf syscall command the user must first attach to
> `bpf_fentry_test1` (or any 1-8), and then execute the BPF_PROG_RUN?
It is how the fentry/fexit/fmod_ret...BPF_PROG_TYPE_TRACIN_xxx prog is setup to
run now in test_run. afaik, these tracing progs require the trampoline setup
before calling the bpf prog, so don't understand how __bpf_prog_test_run_tracing
will work safely.
A selftest will help how this will work without the traompline but may be first
need to understand what it is trying to solve.
next prev parent reply other threads:[~2023-02-06 20:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-03 18:28 [PATCH v2 bpf-next] Add support for tracing programs in BPF_PROG_RUN Grant Seltzer
2023-02-04 6:58 ` Martin KaFai Lau
2023-02-05 17:29 ` Grant Seltzer Richman
2023-02-06 20:37 ` Martin KaFai Lau [this message]
2023-02-07 15:46 ` Grant Seltzer Richman
2023-02-08 1:05 ` Martin KaFai Lau
2023-02-08 15:40 ` Grant Seltzer Richman
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