linux-kernel - Re: [PATCH v1 2/4] x86/mce: dump error msg from severities

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Message-ID: <dceb65c1-9d8a-4675-9354-574deaf141be@linux.alibaba.com>
Date: Fri, 14 Feb 2025 17:29:19 +0800
From: Shuai Xue <xueshuai@...ux.alibaba.com>
To: "Luck, Tony" <tony.luck@...el.com>, "bp@...en8.de" <bp@...en8.de>,
 "nao.horiguchi@...il.com" <nao.horiguchi@...il.com>
Cc: "tglx@...utronix.de" <tglx@...utronix.de>,
 "mingo@...hat.com" <mingo@...hat.com>,
 "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
 "x86@...nel.org" <x86@...nel.org>, "hpa@...or.com" <hpa@...or.com>,
 "linmiaohe@...wei.com" <linmiaohe@...wei.com>,
 "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
 "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "linux-mm@...ck.org" <linux-mm@...ck.org>,
 "baolin.wang@...ux.alibaba.com" <baolin.wang@...ux.alibaba.com>,
 "tianruidong@...ux.alibaba.com" <tianruidong@...ux.alibaba.com>
Subject: Re: [PATCH v1 2/4] x86/mce: dump error msg from severities



在 2025/2/12 00:44, Luck, Tony 写道:
>> The message in severities is useful for identifying the type of MCE that
>> has occurred; dump it if it is valid.
>>
>> Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
>> ---
>>   arch/x86/kernel/cpu/mce/core.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
>> index 2919a077cd66..c1319db45b0a 100644
>> --- a/arch/x86/kernel/cpu/mce/core.c
>> +++ b/arch/x86/kernel/cpu/mce/core.c
>> @@ -1456,6 +1456,8 @@ static void queue_task_work(struct mce_hw_err *err, char *msg, void (*func)(stru
>>        if (count > 1)
>>                return;
>>
>> +     if (msg)
>> +             pr_err("%s\n", msg);
>>        task_work_add(current, &current->mce_kill_me, TWA_RESUME);
>>   }
> 
> This is called from the #MC handler. Is that a safe context to print a console
> message? It wasn't in the past, but maybe changes to how console messages
> are handled have changed this.
> 
> -Tony

#MC is a kind of NMI context, as far as I know, since

commit 42a0bb3f71383b457a7db362f1c69e7afb96732b
printk/nmi: generic solution for safe printk in NMI

print a console message is safe.

Please correct me if I missed anything.

Thanks.
Shuai