From: Masami Hiramatsu <mhiramat@kernel•org>
To: Masami Hiramatsu <mhiramat@kernel•org>
Cc: Jiri Olsa <jolsa@redhat•com>, Alexei Starovoitov <ast@kernel•org>,
Daniel Borkmann <daniel@iogearbox•net>,
Andrii Nakryiko <andrii@kernel•org>,
netdev@vger•kernel.org, bpf@vger•kernel.org,
lkml <linux-kernel@vger•kernel.org>,
Martin KaFai Lau <kafai@fb•com>, Song Liu <songliubraving@fb•com>,
Yonghong Song <yhs@fb•com>,
John Fastabend <john.fastabend@gmail•com>,
KP Singh <kpsingh@chromium•org>,
Steven Rostedt <rostedt@goodmis•org>,
"Naveen N . Rao" <naveen.n.rao@linux•ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel•com>,
"David S . Miller" <davem@davemloft•net>
Subject: Re: [PATCH v5 2/9] fprobe: Add ftrace based probe APIs
Date: Thu, 27 Jan 2022 00:59:52 +0900 [thread overview]
Message-ID: <20220127005952.42dd07ff5f275e61be638283@kernel.org> (raw)
In-Reply-To: <20220126115022.fda21a3face4e97684f5bab9@kernel.org>
On Wed, 26 Jan 2022 11:50:22 +0900
Masami Hiramatsu <mhiramat@kernel•org> wrote:
> > one more question..
> >
> > I'm adding support for user to pass function symbols to bpf fprobe link
> > and I thought I'd pass symbols array to register_fprobe, but I'd need to
> > copy the whole array of strings from user space first, which could take
> > lot of memory considering attachment of 10k+ functions
> >
> > so I'm thinking better way is to resolve symbols already in bpf fprobe
> > link code and pass just addresses to register_fprobe
>
> That is OK. Fprobe accepts either ::syms or ::addrs.
>
> >
> > I assume you want to keep symbol interface, right? could we have some
> > flag ensuring the conversion code is skipped, so we don't go through
> > it twice?
>
> Yeah, we still have many unused bits in fprobe::flags. :)
Instead of that, according to Steve's comment, I would like to introduce
3 registration APIs.
int register_fprobe(struct fprobe *fp, const char *filter, const char *notrace);
int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num);
int register_fprobe_syms(struct fprobe *fp, const char **syms, int num);
The register_fprobe_ips() will not touch the @addrs. You have to set the
correct ftrace location address in the @addrs.
Thank you,
--
Masami Hiramatsu <mhiramat@kernel•org>
next prev parent reply other threads:[~2022-01-26 16:00 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-25 12:11 [PATCH v5 0/9] fprobe: Introduce fprobe function entry/exit probe Masami Hiramatsu
2022-01-25 12:11 ` [PATCH v5 1/9] ftrace: Add ftrace_set_filter_ips function Masami Hiramatsu
2022-01-25 16:06 ` Steven Rostedt
2022-01-25 16:46 ` Jiri Olsa
2022-01-28 2:05 ` Masami Hiramatsu
2022-01-28 9:37 ` Jiri Olsa
2022-01-25 12:11 ` [PATCH v5 2/9] fprobe: Add ftrace based probe APIs Masami Hiramatsu
2022-01-25 16:21 ` Steven Rostedt
2022-01-26 9:06 ` Masami Hiramatsu
2022-01-25 16:41 ` Jiri Olsa
2022-01-25 18:11 ` Jiri Olsa
2022-01-26 2:50 ` Masami Hiramatsu
2022-01-26 15:59 ` Masami Hiramatsu [this message]
2022-01-26 18:39 ` Jiri Olsa
2022-01-25 12:12 ` [PATCH v5 3/9] rethook: Add a generic return hook Masami Hiramatsu
2022-01-25 16:46 ` Steven Rostedt
2022-01-26 0:10 ` Masami Hiramatsu
2022-01-26 5:29 ` Masami Hiramatsu
2022-01-25 12:12 ` [PATCH v5 4/9] rethook: x86: Add rethook x86 implementation Masami Hiramatsu
2022-01-25 12:12 ` [PATCH v5 5/9] ARM: rethook: Add rethook arm implementation Masami Hiramatsu
2022-01-25 12:12 ` [PATCH v5 6/9] arm64: rethook: Add arm64 rethook implementation Masami Hiramatsu
2022-01-25 12:12 ` [PATCH v5 7/9] fprobe: Add exit_handler support Masami Hiramatsu
2022-01-25 17:08 ` Steven Rostedt
2022-01-25 12:13 ` [PATCH v5 8/9] fprobe: Add sample program for fprobe Masami Hiramatsu
2022-01-25 12:13 ` [PATCH v5 9/9] docs: fprobe: Add fprobe description to ftrace-use.rst Masami Hiramatsu
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