From: Steven Rostedt <rostedt@goodmis.org>
To: Song Liu <songliubraving@fb.com>
Cc: open list <linux-kernel@vger.kernel.org>,
bpf <bpf@vger.kernel.org>, Ingo Molnar <mingo@redhat.com>,
Kernel Team <Kernel-team@fb.com>
Subject: Re: ftrace_direct (used by bpf trampoline) conflicts with live patch
Date: Thu, 31 Mar 2022 21:52:33 -0400 [thread overview]
Message-ID: <20220331215233.496479fc@rorschach.local.home> (raw)
In-Reply-To: <20220331214836.663bc7cf@rorschach.local.home>
On Thu, 31 Mar 2022 21:48:36 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> > Does this make sense to you? Did I miss something?
>
> I thought the BPF trampoline does:
>
> call bpf_trace_before_function
> call original_function + X86_PATCH_SIZE
> call bpf_trace_after_function
>
> Thus, the bpf direct trampoline calls the unpatched version of the
> function call making the live patch useless. Or is this not what it
> does?
Or perhaps you are only talking about the part of bpf that does not
trace the end of a function?
-- Steve
next prev parent reply other threads:[~2022-04-01 1:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-01 1:11 ftrace_direct (used by bpf trampoline) conflicts with live patch Song Liu
2022-04-01 1:48 ` Steven Rostedt
2022-04-01 1:52 ` Steven Rostedt [this message]
2022-04-01 21:49 ` Song Liu
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