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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2508FC4332F for ; Mon, 21 Nov 2022 18:20:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=2jIk3m/iBOn10IfM7WUt0WfMgPUSC7mJtsFfv9MfbIs=; b=MwS/bsCnjIJIZl lwRXMe6gNDYp0OfdRPx35tECS9WBhO9v6GRC04u8Vi/H80FsUb5WQUr6UugCfcW6Pg1FQOKuYjLE/ Awt0dkSYbkBlKaB5YCGUv5fymjknBwwayTCFQ8emzyGw2g5LXBZW7LtMi3iUAqO51IpgEqXwE2NOJ Fr7kIXY1WjS5pB435Nd6E9ubZDXUhNc0X3m+Nl5bRq0C1XisWhgMvlcUbPAh3PqO6O6Qj7PDzhEtM Wlzy5YN6A51n6FlF102a7Ac0RQj7vwokazykze9LWyeIdTfadzEhAKS6IAeHN+Uqs1L2BgZMrPP3g RxSft0cMhsUUZqslZu1g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxBNt-00GnYz-Cd; Mon, 21 Nov 2022 18:19:09 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxBNq-00GnWv-OF for linux-arm-kernel@lists.infradead.org; Mon, 21 Nov 2022 18:19:08 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1957761374; Mon, 21 Nov 2022 18:19:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8CAB6C433C1; Mon, 21 Nov 2022 18:19:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669054745; bh=OcZAQMenLu0rqnKBbFddmTe4rP6h4SnbNgtiuE84sag=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QmGXoOQf/yvYCWS/zJOYGVzbk/6LScWFjasUiXlQ9av9cNltUVpyruwrhcLpZCcqR uu88TgeHiDaCs5R7PJFLdGq/zF9aUdfJPsZdAoHd50zhqQr+Bg3Qpp7bAkXn7leoon p37GWe6DRizTOEbZAxI60kkirkL0bgi7IPQgwL67a+NTWDS05gvDE81vwLQVN6gJFa L0rPNHQxQkwpaHVnCnomt4ibhxY4MAabvAt/m30erBxMSez5dCiQUtZxoDBc+XVbFa z2pN6HA0J/IyHDxg/fX8DYhsPQKK1RP7z92X8AI0iHBU8q5HIFPyqFBdNkZVZSCMd/ ZvqGfvJ8d8URA== Date: Mon, 21 Nov 2022 18:18:59 +0000 From: Will Deacon To: Liu Shixin Cc: Catalin Marinas , Denys Vlasenko , Kefeng Wang , Anshuman Khandual , David Hildenbrand , Rafael Aquini , Pasha Tatashin , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] arm64/mm: fix incorrect file_map_count for invalid pmd Message-ID: <20221121181859.GE7645@willie-the-truck> References: <20221121073608.4183459-1-liushixin2@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221121073608.4183459-1-liushixin2@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221121_101906_927648_AF00C195 X-CRM114-Status: GOOD ( 23.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Nov 21, 2022 at 03:36:08PM +0800, Liu Shixin wrote: > The page table check trigger BUG_ON() unexpectedly when split hugepage: > > ------------[ cut here ]------------ > kernel BUG at mm/page_table_check.c:119! > Internal error: Oops - BUG: 00000000f2000800 [#1] SMP > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in: > CPU: 7 PID: 210 Comm: transhuge-stres Not tainted 6.1.0-rc3+ #748 > Hardware name: linux,dummy-virt (DT) > pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : page_table_check_set.isra.0+0x398/0x468 > lr : page_table_check_set.isra.0+0x1c0/0x468 > [...] > Call trace: > page_table_check_set.isra.0+0x398/0x468 > __page_table_check_pte_set+0x160/0x1c0 > __split_huge_pmd_locked+0x900/0x1648 > __split_huge_pmd+0x28c/0x3b8 > unmap_page_range+0x428/0x858 > unmap_single_vma+0xf4/0x1c8 > zap_page_range+0x2b0/0x410 > madvise_vma_behavior+0xc44/0xe78 > do_madvise+0x280/0x698 > __arm64_sys_madvise+0x90/0xe8 > invoke_syscall.constprop.0+0xdc/0x1d8 > do_el0_svc+0xf4/0x3f8 > el0_svc+0x58/0x120 > el0t_64_sync_handler+0xb8/0xc0 > el0t_64_sync+0x19c/0x1a0 > [...] > > On arm64, pmd_leaf() will return true even if the pmd is invalid due to > pmd_present_invalid() check. So in pmdp_invalidate() the file_map_count > will not only decrease once but also increase once. Then in set_pte_at(), > the file_map_count increase again, and so trigger BUG_ON() unexpectedly. > > Add !pmd_present_invalid() check in pmd_user_accessible_page() to fix the > problem. > > Fixes: 42b2547137f5 ("arm64/mm: enable ARCH_SUPPORTS_PAGE_TABLE_CHECK") > Reported-by: Denys Vlasenko > Signed-off-by: Liu Shixin > Acked-by: Pasha Tatashin > Acked-by: David Hildenbrand > Reviewed-by: Kefeng Wang > --- > v1->v2: Update comment and optimize the code by moving p?d_valid() at > first place suggested by Mark. > v2->v3: Replace pmd_valid() with pmd_present_invalid() suggested by Will. > > arch/arm64/include/asm/pgtable.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index edf6625ce965..17afb09f386f 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -863,7 +863,7 @@ static inline bool pte_user_accessible_page(pte_t pte) > > static inline bool pmd_user_accessible_page(pmd_t pmd) > { > - return pmd_leaf(pmd) && (pmd_user(pmd) || pmd_user_exec(pmd)); > + return pmd_leaf(pmd) && !pmd_present_invalid(pmd) && (pmd_user(pmd) || pmd_user_exec(pmd)); > } Acked-by: Will Deacon But please see my comment on v2 about pud_user_exec() for the PUD case. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel