From patchwork Fri Sep 16 05:05:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shuai Xue X-Patchwork-Id: 12978147 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5F17ECAAD8 for ; Fri, 16 Sep 2022 05:05:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229479AbiIPFFx (ORCPT ); Fri, 16 Sep 2022 01:05:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229809AbiIPFFs (ORCPT ); Fri, 16 Sep 2022 01:05:48 -0400 Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A8F34DF15; Thu, 15 Sep 2022 22:05:44 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=xueshuai@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0VPvZJaU_1663304738; Received: from localhost.localdomain(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0VPvZJaU_1663304738) by smtp.aliyun-inc.com; Fri, 16 Sep 2022 13:05:41 +0800 From: Shuai Xue To: rafael@kernel.org, lenb@kernel.org, james.morse@arm.com, tony.luck@intel.com, bp@alien8.de, dave.hansen@linux.intel.com, jarkko@kernel.org, naoya.horiguchi@nec.com, linmiaohe@huawei.com, akpm@linux-foundation.org Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, cuibixuan@linux.alibaba.com, baolin.wang@linux.alibaba.com, zhuo.song@linux.alibaba.com, xueshuai@linux.alibaba.com Subject: [PATCH] ACPI: APEI: do not add task_work for outside context error Date: Fri, 16 Sep 2022 13:05:35 +0800 Message-Id: <20220916050535.26625-1-xueshuai@linux.alibaba.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org If an error is detected as a result of user-space process accessing a corrupt memory location, the CPU may take an abort. Then the platform firmware reports kernel via NMI like notifications, e.g. NOTIFY_SEA, NOTIFY_SOFTWARE_DELEGATED, etc. For NMI like notifications, commit 7f17b4a121d0 ("ACPI: APEI: Kick the memory_failure() queue for synchronous errors") keep track of whether memory_failure() work was queued, and make task_work pending to flush out the queue so that the work is processed before return to user-space. The code use init_mm to check whether the error occurs in user space: if (current->mm != &init_mm) The condition is always true, becase _nobody_ ever has "init_mm" as a real VM any more and should generally just do if (current->mm) as described in active_mm.rst documentation. Then if an error is detected outside of the current execution context (e.g. when detected by a background scrubber), do not add task_work as the original patch intends to do. Fixes: 7f17b4a121d0 ("ACPI: APEI: Kick the memory_failure() queue for synchronous errors") Signed-off-by: Shuai Xue --- drivers/acpi/apei/ghes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index d91ad378c00d..80ad530583c9 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -985,7 +985,7 @@ static void ghes_proc_in_irq(struct irq_work *irq_work) ghes_estatus_cache_add(generic, estatus); } - if (task_work_pending && current->mm != &init_mm) { + if (task_work_pending && current->mm) { estatus_node->task_work.func = ghes_kick_task_work; estatus_node->task_work_cpu = smp_processor_id(); ret = task_work_add(current, &estatus_node->task_work,