linux-kernel - RE: [PATCH] mce: fix missing stack-dumping in mce

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Message-ID: <SJ1PR11MB6083469C1A029CE6C121DF26FCFE9@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date:   Mon, 9 Jan 2023 04:45:26 +0000
From:   "Luck, Tony" <tony.luck@...el.com>
To:     Miaohe Lin <linmiaohe@...wei.com>
CC:     "x86@...nel.org" <x86@...nel.org>, "hpa@...or.com" <hpa@...or.com>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        Borislav Petkov <bp@...en8.de>
Subject: RE: [PATCH] mce: fix missing stack-dumping in mce_panic()

>> Maybe then I can look at some way to suppress the oops dump for the "useless"
>> cases? Or perhaps at least add an extra message that stack dumps from arbitrary
>> machine checks are rarely useful.
>
> IMHO the user will always expect a stack dump when system panic. I'm afraid that if these
> "useless" cases are eliminated, it will cause user confused and trying to find what eats
> the stack dump?

What about the "extra message" option?  Always print the full oops. but for ones from
mce_panic() arrange somehow to add an extra bit of helpful text. Something like this:

1) For poison consumption in kernel code:

"The reason for this panic is consumption of poisoned data by the kernel"

2) For the general machine check case:

"The reason for this panic is a hardware detected error reported as a machine check.
 Note that the stack and register dumps are likely useless to diagnose the root cause
 of this panic."

-Tony