linux-kernel - Re: [PATCHv3 bpf-next 03/13] bpf: Add multi kprobe link

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

Message-ID: <20220316185333.ytyh5irdftjcklk6@ast-mbp.dhcp.thefacebook.com>
Date:   Wed, 16 Mar 2022 11:53:33 -0700
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     Jiri Olsa <jolsa@...nel.org>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Masami Hiramatsu <mhiramat@...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>,
        Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCHv3 bpf-next 03/13] bpf: Add multi kprobe link

On Wed, Mar 16, 2022 at 01:24:09PM +0100, Jiri Olsa wrote:
> +static int
> +kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
> +			   struct pt_regs *regs)
> +{
> +	int err;
> +
> +	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
> +		err = 0;
> +		goto out;
> +	}

That's a heavy hammer.
It's ok-ish for now, but would be good to switch to
__this_cpu_inc_return(*(prog->active)) at some point.
The way fentry/fexit progs do.