From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id EAD4D2E419 for ; Mon, 15 Apr 2024 09:58:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713175105; cv=none; b=bK+x5mwRZKg2fddXXaAXgN7T65znibjwKX/284NHWKqOeZg3rtAiSxeQv6GqBV8ckjNmzGr6Z72vDUcpIqjuFeluZjH2jsk5+8hMeiYwxr8WWmlZ0JROBvEInaK5ALMZSDvVKNzMlb45WCFTHtJdA7HupOO0DesH0Ao38Qsuujg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713175105; c=relaxed/simple; bh=3xDJfyq4svS7Sm0ef9dwg+/++P5TpTpmYYMOLO77S98=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ekYl+CpdQShEPBtvrzuinV07D1afyptHv+NiTgd7BH/akyYpudYWODDYnv92gdDN9BkQyG3wuw2GjPhGDDbBBDCyjpG5JRm7c/zwBk1OGBBRcChvFtRDQMmyZX3tV4SoosHvGH7icYqlFmht7Z1EQEv+NWeAXe3gubwppsHRfRs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 7FBBA2F4; Mon, 15 Apr 2024 02:58:50 -0700 (PDT) Received: from [10.57.75.121] (unknown [10.57.75.121]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0A73F3F792; Mon, 15 Apr 2024 02:58:20 -0700 (PDT) Message-ID: <6dd942e5-2f02-47ca-a348-29cf94decd83@arm.com> Date: Mon, 15 Apr 2024 10:58:19 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V2] arm64/hugetlb: Fix page table walk in huge_pte_alloc() Content-Language: en-GB To: Anshuman Khandual , linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon , Ard Biesheuvel , Mark Rutland , linux-kernel@vger.kernel.org, Dev Jain References: <20240415094003.1812018-1-anshuman.khandual@arm.com> From: Ryan Roberts In-Reply-To: <20240415094003.1812018-1-anshuman.khandual@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 15/04/2024 10:40, 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 > Acked-by: Ard Biesheuvel > Acked-by: Mark Rutland > Signed-off-by: Anshuman Khandual Reviewed-by: Ryan Roberts > --- > This patch applies on v6.9-rc4 > > Changes in V2: > > - Added NULL check for p4dp > > V1: https://lore.kernel.org/all/20240415063110.1795707-1-anshuman.khandual@arm.com/ > > arch/arm64/mm/hugetlbpage.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c > index 0f0e10bb0a95..b872b003a55f 100644 > --- a/arch/arm64/mm/hugetlbpage.c > +++ b/arch/arm64/mm/hugetlbpage.c > @@ -276,7 +276,10 @@ 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); > + if (!p4dp) > + return NULL; > + > pudp = pud_alloc(mm, p4dp, addr); > if (!pudp) > return NULL;