netdev - Re: [bug report] dead loop in generic_perform_write() //Re: [PATCH v7 07/12] iov

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Message-ID: <7e6f9061-1bb9-4d7d-b679-c0183037cbf2@huawei.com>
Date: Tue, 5 Mar 2024 14:57:08 +0800
From: Tong Tiangen <tongtiangen@...wei.com>
To: Linus Torvalds <torvalds@...ux-foundation.org>, David Howells
	<dhowells@...hat.com>
CC: Al Viro <viro@...nel.org>, Jens Axboe <axboe@...nel.dk>, Christoph Hellwig
	<hch@....de>, Christian Brauner <christian@...uner.io>, David Laight
	<David.Laight@...lab.com>, Matthew Wilcox <willy@...radead.org>, Jeff Layton
	<jlayton@...nel.org>, <linux-fsdevel@...r.kernel.org>,
	<linux-block@...r.kernel.org>, <linux-mm@...ck.org>,
	<netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Kefeng Wang
	<wangkefeng.wang@...wei.com>
Subject: Re: [bug report] dead loop in generic_perform_write() //Re: [PATCH v7
 07/12] iov_iter: Convert iterate*() to inline funcs



在 2024/3/5 2:32, Linus Torvalds 写道:
> On Mon, 4 Mar 2024 at 03:56, David Howells <dhowells@...hat.com> wrote:
>>
>> That said, I wonder if:
>>
>>          #ifdef copy_mc_to_kernel
>>
>> should be:
>>
>>          #ifdef CONFIG_ARCH_HAS_COPY_MC
> 
> Hmm. Maybe. We do have that
> 
>    #ifdef copy_mc_to_kernel
> 
> pattern already in <linux/uaccess.h>, so clearly we've done it both ways.
> 
> I personally like the "just test for the thing you are using" model,
> which is then why I did it that way, but I don't have hugely strong
> opinions on it.
> 
>> and whether it's possible to find out dynamically if MCEs can occur at all.
> 
> I really wanted to do something like that, and look at the source page
> to decide "is this a pmem page that can cause machine checks", but I
> didn't find any obvious way to do that.
> 
> Improvement suggestions more than welcome.

I used EINJ to simulate hardware memory error and tested it on an ARM64
  server. This solution can solve the coredump deadloop problem.

I'll sort it out and send the patch.

Thanks,
Tong.

> 
>                 Linus
> .