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[2620:137:e000::1:20]) by mx.google.com with ESMTP id v30-20020a50955e000000b00461540620f1si584524eda.169.2022.10.24.18.43.33; Mon, 24 Oct 2022 18:43:56 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229756AbiJYBib (ORCPT + 99 others); Mon, 24 Oct 2022 21:38:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231253AbiJYBhy (ORCPT ); Mon, 24 Oct 2022 21:37:54 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 270DE9E0F2 for ; Mon, 24 Oct 2022 18:16:35 -0700 (PDT) Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4MxDV40xqfzJn9K; Tue, 25 Oct 2022 09:13:48 +0800 (CST) Received: from dggpemm500014.china.huawei.com (7.185.36.153) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 25 Oct 2022 09:16:33 +0800 Received: from localhost.localdomain (10.175.112.125) by dggpemm500014.china.huawei.com (7.185.36.153) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 25 Oct 2022 09:16:32 +0800 From: Wupeng Ma To: , , CC: , , , , , Subject: [PATCH -next 1/1] mm: hugetlb_vmemmap: Fix WARN_ON in vmemmap_remap_pte Date: Tue, 25 Oct 2022 09:42:15 +0800 Message-ID: <20221025014215.3466904-1-mawupeng1@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500014.china.huawei.com (7.185.36.153) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1747622021897614787?= X-GMAIL-MSGID: =?utf-8?q?1747622021897614787?= From: Ma Wupeng Commit f41f2ed43ca5 ("mm: hugetlb: free the vmemmap pages associated with each HugeTLB page") add vmemmap_remap_pte to remap the tail pages as read-only to catch illegal write operation to the tail page. However this will lead to WARN_ON in arm64 in __check_racy_pte_update() since this may lead to dirty state cleaned. This check is introduced by commit 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits") and the initial check is as follow: BUG_ON(pte_write(*ptep) && !pte_dirty(pte)); Since we do need to mark this pte as read-only to catch illegal write operation to the tail pages, use set_pte to replace set_pte_at to bypass this check. The following shell command can be used to reproduce this WARN_ON in 6.1.0-rc1: echo 1 > /proc/sys/vm/hugetlb_optimize_vmemmap cat /proc/sys/vm/hugetlb_optimize_vmemmap echo 1024 > /proc/sys/vm/nr_overcommit_hugepages mkdir -p /root/hugetlb mount none /root/hugetlb -t hugetlbfs fallocate -l 2g /root/hugetlb/xx & Here is the detail WARN_ON log: ------------[ cut here ]------------ __check_racy_pte_update: racy dirty state clearing: 0x0068000416899f03 -> 0x0060000416898f83 WARNING: CPU: 3 PID: 394 at arch/arm64/include/asm/pgtable.h:318 vmemmap_remap_pte+0x118/0x120 Modules linked in: CPU: 3 PID: 394 Comm: fallocate Not tainted 6.1.0-rc1 #224 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: vmemmap_remap_pte+0x118/0x120 vmemmap_remap_range+0x30c/0x560 hugetlb_vmemmap_optimize+0x158/0x408 __prep_new_huge_page+0x24/0x150 prep_new_huge_page+0x30/0x60 alloc_fresh_huge_page+0x1c4/0x1e0 alloc_surplus_huge_page+0xa0/0x168 alloc_huge_page+0x264/0x5b8 hugetlbfs_fallocate+0x294/0x680 vfs_fallocate+0x12c/0x568 ksys_fallocate+0x50/0xa0 __arm64_sys_fallocate+0x28/0x38 invoke_syscall+0x4c/0x110 el0_svc_common.constprop.0+0x68/0x128 do_el0_svc+0x34/0xd0 el0_svc+0x48/0xb8 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x18c/0x190 ---[ end trace 0000000000000000 ]--- Fixes: f41f2ed43ca5 ("mm: hugetlb: free the vmemmap pages associated with each HugeTLB page") Signed-off-by: Ma Wupeng --- mm/hugetlb_vmemmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index ba2a2596fb4e..cb056265c31e 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -249,7 +249,7 @@ static void vmemmap_remap_pte(pte_t *pte, unsigned long addr, struct page *page = pte_page(*pte); list_add_tail(&page->lru, walk->vmemmap_pages); - set_pte_at(&init_mm, addr, pte, entry); + set_pte(pte, entry); } /*