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From: Leon Hwang <leon.hwang@linux.dev>
To: xu.xin16@zte.com.cn
Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com,
	andrii@kernel.org, eddyz87@gmail.com, memxor@gmail.com,
	martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev,
	jolsa@kernel.org, emil@etsalapatis.com, bpf@vger.kernel.org,
	linux-kernel@vger.kernel.org, xu.xin@linux.dev
Subject: Re: [PATCH bpf-next] bpf:syscall: Log error code on trampoline unlink failure
Date: Thu, 16 Jul 2026 14:56:13 +0800	[thread overview]
Message-ID: <2528a896-a0f4-46ef-a7c5-83c7c8a2980a@linux.dev> (raw)
In-Reply-To: <20260716142613346GZ_NR5Zi4awr3wEReuIMG@zte.com.cn>

On 16/7/26 14:26, xu.xin16@zte.com.cn wrote:
>>> Well, the crash may happen when the kernel is booting, or too hard to reproduce,
>>> in which case, bpftrace does not work.
>>
>>
>> Do you enable kernel.panic_on_warn sysctl?
>>
>> If it's not enabled, the kernel won't crash, I think.
> 
> I'd like to clarify that the panic in our case is not triggered by the WARN itself.
> Instead, the real crash is a use‑after‑free (UAF) that happens when one CPU is
> executing a trampoline while another CPU is concurrently freeing it. This results
> in an illegal instruction (or page fault) at the PC, which is fatal and will panic
> the kernel regardless of panic_on_warn – because it's an Oops with Fatal exception
> in interrupt.


Why not fix the root cause instead?

If you want some help from upstream to fix the root cause, pls provide
the crash dmesg and the reproducing demo.

Thanks,
Leon


  reply	other threads:[~2026-07-16  6:56 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-16  3:34 [PATCH bpf-next] bpf:syscall: Log error code on trampoline unlink failure xu.xin16
2026-07-16  3:45 ` sashiko-bot
2026-07-16  4:58 ` Leon Hwang
2026-07-16  5:55   ` xu.xin16
2026-07-16  6:09     ` Leon Hwang
2026-07-16  6:26       ` xu.xin16
2026-07-16  6:56         ` Leon Hwang [this message]
2026-07-16  7:03           ` xu.xin16
2026-07-16  8:01             ` Leon Hwang

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