From nobody Sun Apr 5 08:26:13 2026 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 1B7E0ECAAA1 for ; Fri, 28 Oct 2022 07:27:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230030AbiJ1H1V (ORCPT ); Fri, 28 Oct 2022 03:27:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229602AbiJ1H1S (ORCPT ); Fri, 28 Oct 2022 03:27:18 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A9DD1B1555 for ; Fri, 28 Oct 2022 00:27:17 -0700 (PDT) Received: from dggpeml500026.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MzDdK1CM2zHvRC; Fri, 28 Oct 2022 15:27:01 +0800 (CST) Received: from localhost.localdomain (10.175.112.125) by dggpeml500026.china.huawei.com (7.185.36.106) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 28 Oct 2022 15:27:15 +0800 From: Yuanzheng Song To: , CC: , , Subject: [PATCH STABLE 5.15] mm/memory: add non-anonymous page check in the copy_present_page() Date: Fri, 28 Oct 2022 07:52:44 +0000 Message-ID: <20221028075244.3112566-1-songyuanzheng@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml500026.china.huawei.com (7.185.36.106) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The vma->anon_vma of the child process may be NULL because the entire vma does not contain anonymous pages. In this case, a BUG will occur when the copy_present_page() passes a copy of a non-anonymous page of that vma to the page_add_new_anon_rmap() to set up new anonymous rmap. ------------[ cut here ]------------ kernel BUG at mm/rmap.c:1052! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: CPU: 4 PID: 4652 Comm: test Not tainted 5.15.75 #1 Hardware name: linux,dummy-virt (DT) pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=3D--) pc : __page_set_anon_rmap+0xc0/0xe8 lr : __page_set_anon_rmap+0xc0/0xe8 sp : ffff80000e773860 x29: ffff80000e773860 x28: fffffc13cf006ec0 x27: ffff04f3ccd68000 x26: ffff04f3c5c33248 x25: 0000000010100073 x24: ffff04f3c53c0a80 x23: 0000000020000000 x22: 0000000000000001 x21: 0000000020000000 x20: fffffc13cf006ec0 x19: 0000000000000000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : ffffdddc5581377c x8 : 0000000000000000 x7 : 0000000000000011 x6 : ffff2717a8433000 x5 : ffff80000e773810 x4 : ffffdddc55400000 x3 : 0000000000000000 x2 : ffffdddc56b20000 x1 : ffff04f3c9a48040 x0 : 0000000000000000 Call trace: __page_set_anon_rmap+0xc0/0xe8 page_add_new_anon_rmap+0x13c/0x200 copy_pte_range+0x6b8/0x1018 copy_page_range+0x3a8/0x5e0 dup_mmap+0x3a0/0x6e8 dup_mm+0x78/0x140 copy_process+0x1528/0x1b08 kernel_clone+0xac/0x610 __do_sys_clone+0x78/0xb0 __arm64_sys_clone+0x30/0x40 invoke_syscall+0x68/0x170 el0_svc_common.constprop.0+0x80/0x250 do_el0_svc+0x48/0xb8 el0_svc+0x48/0x1a8 el0t_64_sync_handler+0xb0/0xb8 el0t_64_sync+0x1a0/0x1a4 Code: 97f899f4 f9400273 17ffffeb 97f899f1 (d4210000) ---[ end trace dc65e5edd0f362fa ]--- Kernel panic - not syncing: Oops - BUG: Fatal exception SMP: stopping secondary CPUs Kernel Offset: 0x5ddc4d400000 from 0xffff800008000000 PHYS_OFFSET: 0xfffffb0c80000000 CPU features: 0x44000cf1,00000806 Memory Limit: none ---[ end Kernel panic - not syncing: Oops - BUG: Fatal exception ]--- This problem has been fixed by the commit ("mm/rmap: split page_dup_rmap() into page_dup_file_rmap() and page_try_dup_anon_rmap()"), but still exists in the linux-5.15.y branch. This patch is not applicable to this version because of the large version differences. Therefore, fix it by adding non-anonymous page check in the copy_present_page(). Cc: stable@vger.kernel.org Fixes: 70e806e4e645 ("mm: Do early cow for pinned pages during fork() for p= tes") Signed-off-by: Yuanzheng Song --- mm/memory.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index a4d0f744a458..5f98778cfff2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -903,6 +903,17 @@ copy_present_page(struct vm_area_struct *dst_vma, stru= ct vm_area_struct *src_vma if (likely(!page_needs_cow_for_dma(src_vma, page))) return 1; =20 + /* + * The vma->anon_vma of the child process may be NULL + * because the entire vma does not contain anonymous pages. + * A BUG will occur when the copy_present_page() passes + * a copy of a non-anonymous page of that vma to the + * page_add_new_anon_rmap() to set up new anonymous rmap. + * Return 1 if the page is not an anonymous page. + */ + if (!PageAnon(page)) + return 1; + new_page =3D *prealloc; if (!new_page) return -EAGAIN; --=20 2.25.1