From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-112.freemail.mail.aliyun.com (out30-112.freemail.mail.aliyun.com [115.124.30.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7223C25634; Thu, 5 Sep 2024 03:09:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.112 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725505802; cv=none; b=Dq+7JeDfO6kDPzP0Sj1ix2LvyFIWpXMgZAkkCnmXLIAkV9NXBsOEK81ycEYGgYK8YEK+vdviIKQFbKxR9AizZmYq8nXy0weTsoNSng/cUkIQEYrFrNVpy2fNYaCXbYUxex5bqLZZ79Le07wfXBIHcqzq/cTz0WNd+dIh0S8OuB4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725505802; c=relaxed/simple; bh=iXpc5nwT9T8D773UI6C/JrWPJ2zYuJYUq2vKFdkUIb8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UBRXjXcFSefk0zT4ZgfMoTIADwMgg+18HK8Vo7sVuELM1p1MC5t2hQf2O+yGAxPrVBhYcJ0nzEKXvEEOxWnOp1KV5MJGju/FpRC90OVEP44bc27LtIhPwEOvbjvJjsC7S4QK2T/JyBuZEvItH6oWdbnY8Ceuwm1dVj2JD0u6WEw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=BAxgEyN2; arc=none smtp.client-ip=115.124.30.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="BAxgEyN2" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1725505797; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=EEK3tU0+O04g/bTYssKY4oUfiGHLfHkoGwUrwDWQSJo=; b=BAxgEyN2X8Qmzl+WgU/TJczxDcEwwwzEuX/aEs80gX4BJ9mq8b7mFyls/gkwj99naX/V3tlg+xGjtuppdFqfLj/TORzMv5320uX3IZE81c3SfrDqWOle0gU/yxObmmnAmF1cNBKs7L1vgRmZz+K1QTwKN60I5/VW8aVwmTiL/R8= Received: from 30.246.162.144(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0WEJd2C3_1725505794) by smtp.aliyun-inc.com; Thu, 05 Sep 2024 11:09:55 +0800 Message-ID: Date: Thu, 5 Sep 2024 11:09:53 +0800 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v12 3/3] ACPI: APEI: handle synchronous exceptions in task work To: Jarkko Sakkinen , 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, tongtiangen@huawei.com, gregkh@linuxfoundation.org, will@kernel.org Cc: linux-acpi@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-edac@vger.kernel.org, x86@kernel.org, justin.he@arm.com, ardb@kernel.org, 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 References: <20221027042445.60108-1-xueshuai@linux.alibaba.com> <20240902030034.67152-4-xueshuai@linux.alibaba.com> From: Shuai Xue In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2024/9/4 00:11, Jarkko Sakkinen 写道: > On Mon Sep 2, 2024 at 6:00 AM EEST, Shuai Xue wrote: >> The memory uncorrected error could be signaled by asynchronous interrupt >> (specifically, SPI in arm64 platform), e.g. when an error is detected by >> a background scrubber, or signaled by synchronous exception >> (specifically, data abort excepction in arm64 platform), e.g. when a CPU >> tries to access a poisoned cache line. Currently, both synchronous and >> asynchronous error use memory_failure_queue() to schedule >> memory_failure() exectute in kworker context. >> >> As a result, when a user-space process is accessing a poisoned data, a >> data abort is taken and the memory_failure() is executed in the kworker >> context: >> >> - will send wrong si_code by SIGBUS signal in early_kill mode, and >> - can not kill the user-space in some cases resulting a synchronous >> error infinite loop >> >> Issue 1: send wrong si_code in early_kill mode >> >> Since commit a70297d22132 ("ACPI: APEI: set memory failure flags as >> MF_ACTION_REQUIRED on synchronous events")', the flag MF_ACTION_REQUIRED >> could be used to determine whether a synchronous exception occurs on >> ARM64 platform. When a synchronous exception is detected, the kernel is >> expected to terminate the current process which has accessed poisoned >> page. This is done by sending a SIGBUS signal with an error code >> BUS_MCEERR_AR, indicating an action-required machine check error on >> read. >> >> However, when kill_proc() is called to terminate the processes who have >> the poisoned page mapped, it sends the incorrect SIGBUS error code >> BUS_MCEERR_AO because the context in which it operates is not the one >> where the error was triggered. >> >> To reproduce this problem: >> >> # STEP1: enable early kill mode >> #sysctl -w vm.memory_failure_early_kill=1 >> vm.memory_failure_early_kill = 1 >> >> # STEP2: inject an UCE error and consume it to trigger a synchronous error >> #einj_mem_uc single >> 0: single vaddr = 0xffffb0d75400 paddr = 4092d55b400 >> injecting ... >> triggering ... >> signal 7 code 5 addr 0xffffb0d75000 >> page not present >> Test passed >> >> The si_code (code 5) from einj_mem_uc indicates that it is BUS_MCEERR_AO >> error and it is not fact. >> >> To fix it, queue memory_failure() as a task_work so that it runs in >> the context of the process that is actually consuming the poisoned data. >> >> After this patch set: > > s/patch set/patch/ > Hi, Jarkko, Will fix the typo in next version. Thank you. Best Regards, Shuai