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 4E180C4345F for ; Mon, 15 Apr 2024 08:38:18 +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=tM3/fDjOP8bl0n9DZQFOK8zOORxGmCcEa6Hi+59kI9c=; b=XNn+7yMUaqiBph l6JLRxxbv4DamGzZFMo9A5DaDLYjg9Ny+WpUXK/8VkEkla/RMG0y7H96HKDo/CSFUIOEfea6egqHX yOUrVe4bW0JgfTsBeNb4TQdVasf6qFS2G6r0OqeBUDE9DEMoQGzr9+tGoDX08mc9nWiXLnR0n3LT/ RvyqtuM/1Z7ovwv0dbOxQQQ7C3wc1QD0iaRXwCD/v1MAWJr1JoyOrUhX1ozegOS7cluOyUEm9MVB0 j/Hyw7Clvqf9ziPn3au9w6T4ttG7IUS2YBgNP/qYIgiJ3T575atXPVmrXglrW5JGuJTQFe6TAUS30 VotPNSjUvHdzd7Js4OjQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rwHqo-00000007ZEC-2pDA; Mon, 15 Apr 2024 08:38:06 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rwHql-00000007ZDi-2dqx for linux-arm-kernel@lists.infradead.org; Mon, 15 Apr 2024 08:38:04 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F31E02F; Mon, 15 Apr 2024 01:38:30 -0700 (PDT) Received: from FVFF77S0Q05N (unknown [10.57.20.152]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 24A683F64C; Mon, 15 Apr 2024 01:38:01 -0700 (PDT) Date: Mon, 15 Apr 2024 09:37:58 +0100 From: Mark Rutland To: Anshuman Khandual Cc: Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Ryan Roberts , linux-kernel@vger.kernel.org, Dev Jain Subject: Re: [PATCH] arm64/hugetlb: Fix page table walk in huge_pte_alloc() Message-ID: References: <20240415063110.1795707-1-anshuman.khandual@arm.com> <5a6cdb94-3849-44bb-81d1-40c9c66852ed@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5a6cdb94-3849-44bb-81d1-40c9c66852ed@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240415_013803_810457_FB021EBD X-CRM114-Status: GOOD ( 22.23 ) 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, Apr 15, 2024 at 12:22:40PM +0530, Anshuman Khandual wrote: > > > On 4/15/24 12:08, Ard Biesheuvel wrote: > > Hello Anshuman, > > > > On Mon, 15 Apr 2024 at 08:31, Anshuman Khandual > > wrote: > >> > >> Currently normal HugeTLB fault ends up crashing the kernel, as p4dp derived > >> from p4d_offset() is an invalid address when PGTABLE_LEVEL = 5. A p4d level > >> entry needs to be allocated when not available while walking the page table > >> during HugeTLB faults. Let's call p4d_alloc() to allocate such entries when > >> required instead of current p4d_offset(). > >> > >> Unable to handle kernel paging request at virtual address ffffffff80000000 > >> Mem abort info: > >> ESR = 0x0000000096000005 > >> EC = 0x25: DABT (current EL), IL = 32 bits > >> SET = 0, FnV = 0 > >> EA = 0, S1PTW = 0 > >> FSC = 0x05: level 1 translation fault > >> Data abort info: > >> ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 > >> CM = 0, WnR = 0, TnD = 0, TagAccess = 0 > >> GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 > >> swapper pgtable: 4k pages, 52-bit VAs, pgdp=0000000081da9000 > >> [ffffffff80000000] pgd=1000000082cec003, p4d=0000000082c32003, pud=0000000000000000 > >> Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP > >> Modules linked in: > >> CPU: 1 PID: 108 Comm: high_addr_hugep Not tainted 6.9.0-rc4 #48 > >> Hardware name: Foundation-v8A (DT) > >> pstate: 01402005 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > >> pc : huge_pte_alloc+0xd4/0x334 > >> lr : hugetlb_fault+0x1b8/0xc68 > >> sp : ffff8000833bbc20 > >> x29: ffff8000833bbc20 x28: fff000080080cb58 x27: ffff800082a7cc58 > >> x26: 0000000000000000 x25: fff0000800378e40 x24: fff00008008d6c60 > >> x23: 00000000de9dbf07 x22: fff0000800378e40 x21: 0004000000000000 > >> x20: 0004000000000000 x19: ffffffff80000000 x18: 1ffe00010011d7a1 > >> x17: 0000000000000001 x16: ffffffffffffffff x15: 0000000000000001 > >> x14: 0000000000000000 x13: ffff8000816120d0 x12: ffffffffffffffff > >> x11: 0000000000000000 x10: fff00008008ebd0c x9 : 0004000000000000 > >> x8 : 0000000000001255 x7 : fff00008003e2000 x6 : 00000000061d54b0 > >> x5 : 0000000000001000 x4 : ffffffff80000000 x3 : 0000000000200000 > >> x2 : 0000000000000004 x1 : 0000000080000000 x0 : 0000000000000000 > >> Call trace: > >> huge_pte_alloc+0xd4/0x334 > >> hugetlb_fault+0x1b8/0xc68 > >> handle_mm_fault+0x260/0x29c > >> do_page_fault+0xfc/0x47c > >> do_translation_fault+0x68/0x74 > >> do_mem_abort+0x44/0x94 > >> el0_da+0x2c/0x9c > >> el0t_64_sync_handler+0x70/0xc4 > >> el0t_64_sync+0x190/0x194 > >> Code: aa000084 cb010084 b24c2c84 8b130c93 (f9400260) > >> ---[ end trace 0000000000000000 ]--- > >> > >> Cc: Catalin Marinas > >> Cc: Will Deacon > >> Cc: Ard Biesheuvel > >> Cc: Ryan Roberts > >> Cc: Mark Rutland > >> Cc: linux-arm-kernel@lists.infradead.org > >> Cc: linux-kernel@vger.kernel.org > >> Fixes: a6bbf5d4d9d1 ("arm64: mm: Add definitions to support 5 levels of paging") > >> Reported-by: Dev Jain > >> Signed-off-by: Anshuman Khandual > >> --- > >> This patch applies on v6.9-rc4 > >> > >> arch/arm64/mm/hugetlbpage.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > > > > Acked-by: Ard Biesheuvel > > > > Thanks for fixing this. One question below. > > > > > >> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c > >> index 0f0e10bb0a95..5c819459555a 100644 > >> --- a/arch/arm64/mm/hugetlbpage.c > >> +++ b/arch/arm64/mm/hugetlbpage.c > >> @@ -276,7 +276,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, > >> pte_t *ptep = NULL; > >> > >> pgdp = pgd_offset(mm, addr); > >> - p4dp = p4d_offset(pgdp, addr); > >> + p4dp = p4d_alloc(mm, pgdp, addr); > > > > Shouldn't we check p4dp for NULL here? > > Sure, makes sense. I will add a check for p4dp, just like pudp below. With that: Acked-by: Mark Rutland Mark. > > > > >> pudp = pud_alloc(mm, p4dp, addr); > >> if (!pudp) > >> return NULL; > >> -- > >> 2.25.1 > >> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel