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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 22B69C433FE for ; Mon, 20 Sep 2021 18:41:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D68C61177 for ; Mon, 20 Sep 2021 18:41:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348826AbhITSmt (ORCPT ); Mon, 20 Sep 2021 14:42:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:53064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381474AbhITSiR (ORCPT ); Mon, 20 Sep 2021 14:38:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B615A63320; Mon, 20 Sep 2021 17:29:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632158994; bh=k6rVEvMUvMNegWfy2BJWTK8oq5CB5o7Y15+9iq8TfwE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LCLqhilOA3U3VLhLDXomrVeEGPsEKiFdvfEmFcAy30SQbDvBCoPaDTk5c+VE1TJPz werXo0NLSm2zxXVVSL97B+CQUTSIGBiNuC9BxjoBF4FvbknLZIsXyx+pz9WuAL9qlu hQE/jkdItl9/M0iTj5GJ9G0AuSrQ97LImgmoPeYU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sander Eikelenboom , Juergen Gross Subject: [PATCH 5.14 005/168] xen: fix usage of pmd_populate in mremap for pv guests Date: Mon, 20 Sep 2021 18:42:23 +0200 Message-Id: <20210920163921.823283166@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210920163921.633181900@linuxfoundation.org> References: <20210920163921.633181900@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Juergen Gross commit 36c9b5929b7094ea19a78827c0ede20d2e0e6c9c upstream. Commit 0881ace292b662 ("mm/mremap: use pmd/pud_poplulate to update page table entries") introduced a regression when running as Xen PV guest. Today pmd_populate() for Xen PV assumes that the PFN inserted is referencing a not yet used page table. In case of move_normal_pmd() this is not true, resulting in WARN splats like: [34321.304270] ------------[ cut here ]------------ [34321.304277] WARNING: CPU: 0 PID: 23628 at arch/x86/xen/multicalls.c:102 xen_mc_flush+0x176/0x1a0 [34321.304288] Modules linked in: [34321.304291] CPU: 0 PID: 23628 Comm: apt-get Not tainted 5.14.1-20210906-doflr-mac80211debug+ #1 [34321.304294] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640) , BIOS V1.8B1 09/13/2010 [34321.304296] RIP: e030:xen_mc_flush+0x176/0x1a0 [34321.304300] Code: 89 45 18 48 c1 e9 3f 48 89 ce e9 20 ff ff ff e8 60 03 00 00 66 90 5b 5d 41 5c 41 5d c3 48 c7 45 18 ea ff ff ff be 01 00 00 00 <0f> 0b 8b 55 00 48 c7 c7 10 97 aa 82 31 db 49 c7 c5 38 97 aa 82 65 [34321.304303] RSP: e02b:ffffc90000a97c90 EFLAGS: 00010002 [34321.304305] RAX: ffff88807d416398 RBX: ffff88807d416350 RCX: ffff88807d416398 [34321.304306] RDX: 0000000000000001 RSI: 0000000000000001 RDI: deadbeefdeadf00d [34321.304308] RBP: ffff88807d416300 R08: aaaaaaaaaaaaaaaa R09: ffff888006160cc0 [34321.304309] R10: deadbeefdeadf00d R11: ffffea000026a600 R12: 0000000000000000 [34321.304310] R13: ffff888012f6b000 R14: 0000000012f6b000 R15: 0000000000000001 [34321.304320] FS: 00007f5071177800(0000) GS:ffff88807d400000(0000) knlGS:0000000000000000 [34321.304322] CS: 10000e030 DS: 0000 ES: 0000 CR0: 0000000080050033 [34321.304323] CR2: 00007f506f542000 CR3: 00000000160cc000 CR4: 0000000000000660 [34321.304326] Call Trace: [34321.304331] xen_alloc_pte+0x294/0x320 [34321.304334] move_pgt_entry+0x165/0x4b0 [34321.304339] move_page_tables+0x6fa/0x8d0 [34321.304342] move_vma.isra.44+0x138/0x500 [34321.304345] __x64_sys_mremap+0x296/0x410 [34321.304348] do_syscall_64+0x3a/0x80 [34321.304352] entry_SYSCALL_64_after_hwframe+0x44/0xae [34321.304355] RIP: 0033:0x7f507196301a [34321.304358] Code: 73 01 c3 48 8b 0d 76 0e 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 19 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 46 0e 0c 00 f7 d8 64 89 01 48 [34321.304360] RSP: 002b:00007ffda1eecd38 EFLAGS: 00000246 ORIG_RAX: 0000000000000019 [34321.304362] RAX: ffffffffffffffda RBX: 000056205f950f30 RCX: 00007f507196301a [34321.304363] RDX: 0000000001a00000 RSI: 0000000001900000 RDI: 00007f506dc56000 [34321.304364] RBP: 0000000001a00000 R08: 0000000000000010 R09: 0000000000000004 [34321.304365] R10: 0000000000000001 R11: 0000000000000246 R12: 00007f506dc56060 [34321.304367] R13: 00007f506dc56000 R14: 00007f506dc56060 R15: 000056205f950f30 [34321.304368] ---[ end trace a19885b78fe8f33e ]--- [34321.304370] 1 of 2 multicall(s) failed: cpu 0 [34321.304371] call 2: op=12297829382473034410 arg=[aaaaaaaaaaaaaaaa] result=-22 Fix that by modifying xen_alloc_ptpage() to only pin the page table in case it wasn't pinned already. Fixes: 0881ace292b662 ("mm/mremap: use pmd/pud_poplulate to update page table entries") Cc: Reported-by: Sander Eikelenboom Tested-by: Sander Eikelenboom Signed-off-by: Juergen Gross Link: https://lore.kernel.org/r/20210908073640.11299-1-jgross@suse.com Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- arch/x86/xen/mmu_pv.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -1518,14 +1518,17 @@ static inline void xen_alloc_ptpage(stru if (pinned) { struct page *page = pfn_to_page(pfn); - if (static_branch_likely(&xen_struct_pages_ready)) + pinned = false; + if (static_branch_likely(&xen_struct_pages_ready)) { + pinned = PagePinned(page); SetPagePinned(page); + } xen_mc_batch(); __set_pfn_prot(pfn, PAGE_KERNEL_RO); - if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS) + if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS && !pinned) __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn); xen_mc_issue(PARAVIRT_LAZY_MMU);