From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Donglin Peng <dolinux.peng@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
linux-trace-kernel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
bpf <bpf@vger.kernel.org>, Sven Schnelle <svens@linux.ibm.com>,
Alexei Starovoitov <ast@kernel.org>
Subject: Re: [PATCH v2 2/9] bpf/btf: tracing: Move finding func-proto API and getting func-param API to BTF
Date: Thu, 20 Jul 2023 00:15:22 +0900 [thread overview]
Message-ID: <20230720001522.4aaadaf77d037ccdc7e4b83e@kernel.org> (raw)
In-Reply-To: <CAErzpmtJF4tjHCyYdHgiX_-vp39tdc=3iNmMhQ6SnFVicqZWrg@mail.gmail.com>
On Wed, 19 Jul 2023 10:09:48 +0800
Donglin Peng <dolinux.peng@gmail.com> wrote:
> On Wed, Jul 19, 2023 at 7:03 AM Masami Hiramatsu <mhiramat@kernel.org> wrote:
> >
> > On Tue, 18 Jul 2023 10:11:01 -0700
> > Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> >
> > > On Tue, Jul 18, 2023 at 6:56 AM Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > > >
> > > > On Tue, 18 Jul 2023 19:44:31 +0900
> > > > Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> > > >
> > > > > > > static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr,
> > > > > > > bool tracepoint)
> > > > > > > {
> > > > > > > + struct btf *btf = traceprobe_get_btf();
> > > > > >
> > > > > > I found that traceprobe_get_btf() only returns the vmlinux's btf. But
> > > > > > if the function is
> > > > > > defined in a kernel module, we should get the module's btf.
> > > > > >
> > > > >
> > > > > Good catch! That should be a separated fix (or improvement?)
> > > > > I think it's better to use btf_get() and btf_put(), and pass btf via
> > > > > traceprobe_parse_context.
> > > >
> > > > Hmm, it seems that there is no exposed API to get the module's btf.
> > > > Should I use btf_idr and btf_idr_lock directly to find the corresponding
> > > > btf? If there isn't yet, I will add it too.
> > >
> > > There is bpf_find_btf_id.
> > > Probably drop 'static' from it and use it.
> >
> > Thanks! BTW, that API seems to search BTF type info by name. If user want to
> > specify a module name, do we need a new API? (Or expand the function to parse
> > a module name in given name?)
>
> btf_get_module_btf can be used to get a module's btf, but we have to use
> find_module to get the module by its name firstly.
Thanks for the info! OK, this will be useful.
>
> >
> > Thank you,
> > --
> > Masami Hiramatsu (Google) <mhiramat@kernel.org>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2023-07-19 15:15 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-17 15:23 [PATCH v2 0/9] tracing: Improbe BTF support on probe events Masami Hiramatsu (Google)
2023-07-17 15:23 ` [PATCH v2 1/9] tracing/probes: Fix to add NULL check for BTF APIs Masami Hiramatsu (Google)
2023-07-17 15:23 ` [PATCH v2 2/9] bpf/btf: tracing: Move finding func-proto API and getting func-param API to BTF Masami Hiramatsu (Google)
2023-07-17 18:39 ` Steven Rostedt
2023-07-17 23:46 ` Masami Hiramatsu
2023-07-17 23:51 ` Alexei Starovoitov
2023-07-18 1:03 ` Masami Hiramatsu
2023-07-17 23:51 ` Steven Rostedt
2023-07-18 1:02 ` Masami Hiramatsu
2023-07-18 2:40 ` Donglin Peng
2023-07-18 10:44 ` Masami Hiramatsu
2023-07-18 13:56 ` Masami Hiramatsu
2023-07-18 17:11 ` Alexei Starovoitov
2023-07-18 23:03 ` Masami Hiramatsu
2023-07-18 23:12 ` Alexei Starovoitov
2023-07-19 15:17 ` Masami Hiramatsu
2023-07-19 2:09 ` Donglin Peng
2023-07-19 15:15 ` Masami Hiramatsu [this message]
2023-07-19 12:36 ` Alan Maguire
2023-07-19 15:24 ` Masami Hiramatsu
2023-07-19 15:49 ` Alan Maguire
2023-07-17 15:23 ` [PATCH v2 3/9] bpf/btf: Add a function to search a member of a struct/union Masami Hiramatsu (Google)
2023-07-20 22:34 ` Alan Maguire
2023-07-21 14:22 ` Masami Hiramatsu
2023-07-17 15:23 ` [PATCH v2 4/9] tracing/probes: Support BTF based data structure field access Masami Hiramatsu (Google)
2023-07-20 22:51 ` Alan Maguire
2023-07-21 14:22 ` Masami Hiramatsu
2023-07-17 15:24 ` [PATCH v2 5/9] tracing/probes: Support BTF field access from $retval Masami Hiramatsu (Google)
2023-07-17 15:24 ` [PATCH v2 6/9] tracing/probes: Add string type check with BTF Masami Hiramatsu (Google)
2023-07-17 15:24 ` [PATCH v2 7/9] tracing/fprobe-event: Assume fprobe is a return event by $retval Masami Hiramatsu (Google)
2023-07-17 15:24 ` [PATCH v2 8/9] selftests/ftrace: Add BTF fields access testcases Masami Hiramatsu (Google)
2023-07-20 23:00 ` Alan Maguire
2023-07-21 1:42 ` Masami Hiramatsu
2023-07-17 15:24 ` [PATCH v2 9/9] Documentation: tracing: Update fprobe event example with BTF field Masami Hiramatsu (Google)
2023-07-20 22:53 ` Alan Maguire
2023-07-21 13:58 ` Masami Hiramatsu
2023-07-19 9:02 ` [PATCH v2 0/9] tracing: Improbe BTF support on probe events Alan Maguire
2023-07-19 16:01 ` Masami Hiramatsu
2023-07-20 21:50 ` Alan Maguire
2023-07-25 23:45 ` Masami Hiramatsu
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