From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA953C2B9F4 for ; Mon, 28 Jun 2021 14:25:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D04BF613CB for ; Mon, 28 Jun 2021 14:25:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233892AbhF1O1n (ORCPT ); Mon, 28 Jun 2021 10:27:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:55032 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233421AbhF1OWU (ORCPT ); Mon, 28 Jun 2021 10:22:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2149061C95; Mon, 28 Jun 2021 14:19:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624889980; bh=/B3PocEAdMGFBNlkc9BqDH+WNw/ZyVBO3rD7Cb0QLyE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q92LE29AdQ6WLeDGMIp+CCLgIAiGFR73+TeJ8uJkLfusDjCiaVdQSdOue7L/8TqxN 5tQCknYy/hVt21JX4zJMZXFS5Byr+bJ4nPiY8y6dLEJZvdPyvxIHzPfDExIY3UWdbe JOkfULIB0XPoTLZDvT8j5PEULeuJPKZaiw1EBhyWArDIdJLY595KhzQk+J0CuC3hRL NAEVfBv/5EWoVuBq1VnObUNJYKsZX/324io+jYWVyooLSb2a8IUj+ZP7AkoIJnyJ8l cS1NSh3vX2FoPi0We0nIg5ASRgty+Iq1WRFQXA0nTdpWz3l3ydl9sV3KKpUmmMizDP +7Fl/LkuH4cIQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tony Luck , Naoya Horiguchi , Borislav Petkov , Oscar Salvador , Aili Yao , Andy Lutomirski , Borislav Petkov , David Hildenbrand , Jue Wang , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman Subject: [PATCH 5.12 081/110] mm/memory-failure: use a mutex to avoid memory_failure() races Date: Mon, 28 Jun 2021 10:17:59 -0400 Message-Id: <20210628141828.31757-82-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628141828.31757-1-sashal@kernel.org> References: <20210628141828.31757-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.12.14-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.12.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.12.14-rc1 X-KernelTest-Deadline: 2021-06-30T14:18+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tony Luck commit 171936ddaf97e6f4e1264f4128bb5cf15691339c upstream. Patch series "mm,hwpoison: fix sending SIGBUS for Action Required MCE", v5. I wrote this patchset to materialize what I think is the current allowable solution mentioned by the previous discussion [1]. I simply borrowed Tony's mutex patch and Aili's return code patch, then I queued another one to find error virtual address in the best effort manner. I know that this is not a perfect solution, but should work for some typical case. [1]: https://lore.kernel.org/linux-mm/20210331192540.2141052f@alex-virtual-machine/ This patch (of 2): There can be races when multiple CPUs consume poison from the same page. The first into memory_failure() atomically sets the HWPoison page flag and begins hunting for tasks that map this page. Eventually it invalidates those mappings and may send a SIGBUS to the affected tasks. But while all that work is going on, other CPUs see a "success" return code from memory_failure() and so they believe the error has been handled and continue executing. Fix by wrapping most of the internal parts of memory_failure() in a mutex. [akpm@linux-foundation.org: make mf_mutex local to memory_failure()] Link: https://lkml.kernel.org/r/20210521030156.2612074-1-nao.horiguchi@gmail.com Link: https://lkml.kernel.org/r/20210521030156.2612074-2-nao.horiguchi@gmail.com Signed-off-by: Tony Luck Signed-off-by: Naoya Horiguchi Reviewed-by: Borislav Petkov Reviewed-by: Oscar Salvador Cc: Aili Yao Cc: Andy Lutomirski Cc: Borislav Petkov Cc: David Hildenbrand Cc: Jue Wang Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memory-failure.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 704d05057d8c..2dd60ad81216 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1429,9 +1429,10 @@ int memory_failure(unsigned long pfn, int flags) struct page *hpage; struct page *orig_head; struct dev_pagemap *pgmap; - int res; + int res = 0; unsigned long page_flags; bool retry = true; + static DEFINE_MUTEX(mf_mutex); if (!sysctl_memory_failure_recovery) panic("Memory failure on page %lx", pfn); @@ -1449,13 +1450,18 @@ int memory_failure(unsigned long pfn, int flags) return -ENXIO; } + mutex_lock(&mf_mutex); + try_again: - if (PageHuge(p)) - return memory_failure_hugetlb(pfn, flags); + if (PageHuge(p)) { + res = memory_failure_hugetlb(pfn, flags); + goto unlock_mutex; + } + if (TestSetPageHWPoison(p)) { pr_err("Memory failure: %#lx: already hardware poisoned\n", pfn); - return 0; + goto unlock_mutex; } orig_head = hpage = compound_head(p); @@ -1488,17 +1494,19 @@ try_again: res = MF_FAILED; } action_result(pfn, MF_MSG_BUDDY, res); - return res == MF_RECOVERED ? 0 : -EBUSY; + res = res == MF_RECOVERED ? 0 : -EBUSY; } else { action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED); - return -EBUSY; + res = -EBUSY; } + goto unlock_mutex; } if (PageTransHuge(hpage)) { if (try_to_split_thp_page(p, "Memory Failure") < 0) { action_result(pfn, MF_MSG_UNSPLIT_THP, MF_IGNORED); - return -EBUSY; + res = -EBUSY; + goto unlock_mutex; } VM_BUG_ON_PAGE(!page_count(p), p); } @@ -1522,7 +1530,7 @@ try_again: if (PageCompound(p) && compound_head(p) != orig_head) { action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED); res = -EBUSY; - goto out; + goto unlock_page; } /* @@ -1542,14 +1550,14 @@ try_again: num_poisoned_pages_dec(); unlock_page(p); put_page(p); - return 0; + goto unlock_mutex; } if (hwpoison_filter(p)) { if (TestClearPageHWPoison(p)) num_poisoned_pages_dec(); unlock_page(p); put_page(p); - return 0; + goto unlock_mutex; } /* @@ -1573,7 +1581,7 @@ try_again: if (!hwpoison_user_mappings(p, pfn, flags, &p)) { action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED); res = -EBUSY; - goto out; + goto unlock_page; } /* @@ -1582,13 +1590,15 @@ try_again: if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) { action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED); res = -EBUSY; - goto out; + goto unlock_page; } identify_page_state: res = identify_page_state(pfn, p, page_flags); -out: +unlock_page: unlock_page(p); +unlock_mutex: + mutex_unlock(&mf_mutex); return res; } EXPORT_SYMBOL_GPL(memory_failure); -- 2.30.2