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Date: Mon, 18 Dec 2023 07:53:53 +0100
From: Greg KH <gregkh@linuxfoundation.org>
To: Shuai Xue <xueshuai@linux.alibaba.com>
Cc: bp@alien8.de, rafael@kernel.org, wangkefeng.wang@huawei.com,
	tanxiaofei@huawei.com, mawupeng1@huawei.com, tony.luck@intel.com,
	linmiaohe@huawei.com, naoya.horiguchi@nec.com, james.morse@arm.com,
	will@kernel.org, jarkko@kernel.org, linux-acpi@vger.kernel.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
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	ying.huang@intel.com, ashish.kalra@amd.com,
	baolin.wang@linux.alibaba.com, tglx@linutronix.de, mingo@redhat.com,
	dave.hansen@linux.intel.com, lenb@kernel.org, hpa@zytor.com,
	robert.moore@intel.com, lvying6@huawei.com, xiexiuqi@huawei.com,
	zhuo.song@linux.alibaba.com
Subject: Re: [PATCH v10 1/4] ACPI: APEI: set memory failure flags as
 MF_ACTION_REQUIRED on synchronous events
Message-ID: <2023121847-resistant-fleshy-0c4b@gregkh>
References: <20221027042445.60108-1-xueshuai@linux.alibaba.com>
 <20231218064521.37324-2-xueshuai@linux.alibaba.com>
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In-Reply-To: <20231218064521.37324-2-xueshuai@linux.alibaba.com>

On Mon, Dec 18, 2023 at 02:45:18PM +0800, Shuai Xue wrote:
> There are two major types of uncorrected recoverable (UCR) errors :
> 
> - Synchronous error: The error is detected and raised at the point of the
>   consumption in the execution flow, e.g. when a CPU tries to access
>   a poisoned cache line. The CPU will take a synchronous error exception
>   such as Synchronous External Abort (SEA) on Arm64 and Machine Check
>   Exception (MCE) on X86. OS requires to take action (for example, offline
>   failure page/kill failure thread) to recover this uncorrectable error.
> 
> - Asynchronous error: The error is detected out of processor execution
>   context, e.g. when an error is detected by a background scrubber. Some data
>   in the memory are corrupted. But the data have not been consumed. OS is
>   optional to take action to recover this uncorrectable error.
> 
> When APEI firmware first is enabled, a platform may describe one error
> source for the handling of synchronous errors (e.g. MCE or SEA notification
> ), or for handling asynchronous errors (e.g. SCI or External Interrupt
> notification). In other words, we can distinguish synchronous errors by
> APEI notification. For synchronous errors, kernel will kill the current
> process which accessing the poisoned page by sending SIGBUS with
> BUS_MCEERR_AR. In addition, for asynchronous errors, kernel will notify the
> process who owns the poisoned page by sending SIGBUS with BUS_MCEERR_AO in
> early kill mode. However, the GHES driver always sets mf_flags to 0 so that
> all synchronous errors are handled as asynchronous errors in memory failure.
> 
> To this end, set memory failure flags as MF_ACTION_REQUIRED on synchronous
> events.
> 
> Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
> Tested-by: Ma Wupeng <mawupeng1@huawei.com>
> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> Reviewed-by: Xiaofei Tan <tanxiaofei@huawei.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Reviewed-by: James Morse <james.morse@arm.com>
> ---
>  drivers/acpi/apei/ghes.c | 29 +++++++++++++++++++++++------
>  1 file changed, 23 insertions(+), 6 deletions(-)
> 

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>