linux-kernel - Re: [PATCH v12 bpf-next 02/12] fprobe: Add ftrace based probe APIs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Thu, 8 Jun 2023 18:51:42 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Masami Hiramatsu <mhiramat@...nel.org>
Cc:     Jiri Olsa <jolsa@...nel.org>, Alexei Starovoitov <ast@...nel.org>,
        Andrii Nakryiko <andrii.nakryiko@...il.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>, netdev@...r.kernel.org,
        bpf@...r.kernel.org, lkml <linux-kernel@...r.kernel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>,
        "Naveen N . Rao" <naveen.n.rao@...ux.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>,
        "David S . Miller" <davem@...emloft.net>
Subject: Re: [PATCH v12 bpf-next 02/12] fprobe: Add ftrace based probe APIs

On Tue, 15 Mar 2022 23:00:38 +0900
Masami Hiramatsu <mhiramat@...nel.org> wrote:

> +static void fprobe_init(struct fprobe *fp)
> +{
> +	fp->nmissed = 0;
> +	fp->ops.func = fprobe_handler;
> +	fp->ops.flags |= FTRACE_OPS_FL_SAVE_REGS;
> +}
> +

Masami,

I thought one of the advantages of fprobes over kprobes was that it did not
need to use SAVE_REGS, as that causes more overhead than SAVE_ARGS?

If fprobes uses save regs, what is the advantage of it over kprobes?

-- Steve