linux-kernel - Re: [BUG] RCU Detected Stall in sys_process_vm

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Message-ID: <0b864cd0-e763-4266-a80a-cfa69ad60ee1@intel.com>
Date: Fri, 23 May 2025 10:34:31 -0700
From: Dave Hansen <dave.hansen@...el.com>
To: Guoyu Yin <y04609127@...il.com>, akpm@...ux-foundation.org
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
 dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
 tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
 hpa@...or.com
Subject: Re: [BUG] RCU Detected Stall in sys_process_vm_writev

On 5/18/25 22:19, Guoyu Yin wrote:
> I discovered a kernel crash using the Syzkaller framework, described
> as "INFO: rcu detected stall in sys_process_vm_writev". This issue
> occurs during the execution of the sys_process_vm_writev system call,
> where RCU detects a stall on CPU 0.
Guoyu,

Could you tell us a little more about the overall environment here? It
seems like you're running syzkaller and just reporting whenever you see
a splat. Is that about right? Could you tell us a little more about why
you are doing this? What is your goal?

I think Steve's advice he gave to en eerily similar report applies to
this one as well:

https://lore.kernel.org/all/20250521133137.1b2f2cac@gandalf.local.home/

Feel free to _run_ with KASAN enabled, but please don't report issues
unless you can reproduce without KASAN. Unless it's an actual KASAN
error report, of course.

But, in general syzkaller produces a ton of noise. Unless you have a
reproducer or a _clear_ bug, I'm not sure it's very worth sending these
reports. There's honestly not much we can do with them.