linux-kernel - Re: [PATCH v2 1/5] x86/mce: Collect error message for severities below MCE_PANIC

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Message-ID: <b3c12f1f-f27a-44f0-b32c-32b58e6e926c@linux.alibaba.com>
Date: Tue, 18 Feb 2025 17:39:33 +0800
From: Shuai Xue <xueshuai@...ux.alibaba.com>
To: Borislav Petkov <bp@...en8.de>
Cc: tony.luck@...el.com, nao.horiguchi@...il.com, tglx@...utronix.de,
 mingo@...hat.com, dave.hansen@...ux.intel.com, x86@...nel.org,
 hpa@...or.com, linmiaohe@...wei.com, akpm@...ux-foundation.org,
 peterz@...radead.org, jpoimboe@...nel.org, linux-edac@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-mm@...ck.org,
 baolin.wang@...ux.alibaba.com, tianruidong@...ux.alibaba.com
Subject: Re: [PATCH v2 1/5] x86/mce: Collect error message for severities
 below MCE_PANIC_SEVERITY

在 2025/2/18 15:58, Borislav Petkov 写道:
> On Mon, Feb 17, 2025 at 02:33:31PM +0800, Shuai Xue wrote:
>> Currently, mce_no_way_out() only collects error messages when the error
>> severity is equal to `MCE_PANIC_SEVERITY`. To improve diagnostics,
>> modify the behavior to also collect error messages when the severity is
>> less than `MCE_PANIC_SEVERITY`.
> 
> That function is literally called "no way out" as in, is the error severe
> enough so that there is no way out.
> 
> Now you went and stomped all over that to "improve diagnostics". What
> diagnostsics? Your commit messages need to explain in detail why exactly
> a patch exists.
> 
> So nope.
> 

Hi, Borislav,

Thank you for reply.

The msg in predefined `severities`, e.g.

	MCESEV(
		AO, "Action optional: last level cache writeback error",
		SER, MASK(MCI_UC_AR|MCACOD, MCI_STATUS_UC|MCACOD_L3WB)
		),

is helpful for users to know what kind of MCE is happened. For a fatal machine
check, kernel panic use the message and I want to extend to collect the message
and print it out for non-fatal one.

If you don't object, let's go on to discuss how to implement it.
Otherwise, you can ignore the following response.

Yes, mce_no_way_out() means "no way out" literally. It only collects message
for MCE_PANIC_SEVERITY but use in common path. So I used this function to
extend it to non-fatal, assuming it was obvious.

Is __mc_scan_banks() a proper function to extend?

Thanks.
Shuai