netdev - Re: [PATCH] net: Add tcp_drop

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: <CANn89iJuShCmidCi_ZkYABtmscwbVjhuDta1MS5LxV_4H9tKOA@mail.gmail.com>
Date: Wed, 23 Oct 2024 15:01:20 +0200
From: Eric Dumazet <edumazet@...gle.com>
To: Yafang Shao <laoar.shao@...il.com>
Cc: davem@...emloft.net, dsahern@...nel.org, kuba@...nel.org, 
	pabeni@...hat.com, rostedt@...dmis.org, mhiramat@...nel.org, 
	mathieu.desnoyers@...icios.com, netdev@...r.kernel.org, 
	linux-trace-kernel@...r.kernel.org, Menglong Dong <menglong8.dong@...il.com>
Subject: Re: [PATCH] net: Add tcp_drop_reason tracepoint

On Wed, Oct 23, 2024 at 2:33 PM Yafang Shao <laoar.shao@...il.com> wrote:
>
> We previously hooked the tcp_drop_reason() function using BPF to monitor
> TCP drop reasons. However, after upgrading our compiler from GCC 9 to GCC
> 11, tcp_drop_reason() is now inlined, preventing us from hooking into it.
> To address this, it would be beneficial to introduce a dedicated tracepoint
> for monitoring.

This patch would require changes in user space tracers.
I am surprised no one came up with a noinline variant.

__bpf_kfunc is using

#define __bpf_kfunc __used __retain noinline

I would rather not have include/trace/events/tcp.h becoming the
biggest file in TCP stack...