linux-kernel - Re: [PATCH bpf v2 2/2] selftests/bpf: Add socket filter attach test

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: <CANk7y0hQWOL3OW8Ok4e-kp7Brn5Zq6H5+EfS=mVtoVd+AUxZmA@mail.gmail.com>
Date: Thu, 14 Aug 2025 13:23:55 +0200
From: Puranjay Mohan <puranjay12@...il.com>
To: Eduard Zingerman <eddyz87@...il.com>
Cc: KaFai Wan <kafai.wan@...ux.dev>, puranjay@...nel.org, xukuohai@...weicloud.com, 
	ast@...nel.org, daniel@...earbox.net, john.fastabend@...il.com, 
	andrii@...nel.org, martin.lau@...ux.dev, song@...nel.org, 
	yonghong.song@...ux.dev, kpsingh@...nel.org, sdf@...ichev.me, 
	haoluo@...gle.com, jolsa@...nel.org, mykolal@...com, shuah@...nel.org, 
	mrpre@....com, linux-kernel@...r.kernel.org, bpf@...r.kernel.org, 
	linux-kselftest@...r.kernel.org
Subject: Re: [PATCH bpf v2 2/2] selftests/bpf: Add socket filter attach test

On Thu, Aug 14, 2025 at 2:35 AM Eduard Zingerman <eddyz87@...il.com> wrote:
>
> On Wed, 2025-08-13 at 23:29 +0800, KaFai Wan wrote:
> > This test verifies socket filter attachment functionality on architectures
> > supporting either BPF JIT compilation or the interpreter.
> >
> > It specifically validates the fallback to interpreter behavior when JIT fails,
> > particularly targeting ARMv6 devices with the following configuration:
> >   # CONFIG_BPF_JIT_ALWAYS_ON is not set
> >   CONFIG_BPF_JIT_DEFAULT_ON=y
> >
> > Signed-off-by: KaFai Wan <kafai.wan@...ux.dev>
> > ---
>
> This test should not be landed as-is, first let's do an analysis for
> why the program fails to jit compile on arm.
>
> I modified kernel to dump BPF program before jit attempt, but don't
> see anything obviously wrong with it.  The patch to get disassembly
> and disassembly itself with resolved kallsyms are attached.
>
> Can someone with access to ARM vm/machine take a looks at this?
> Puranjay, Xu, would you have some time?

Hi Eduard,
Thanks for the email, I will look into it.

Let me try to boot a kernel on ARMv6 qemu and reproduce this.

Thanks,
Puranjay