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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 0A27CC3F2D2 for ; Thu, 5 Mar 2020 19:22:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8E444207FD for ; Thu, 5 Mar 2020 19:22:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="ASgy7a0Z" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8E444207FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E68B76B0007; Thu, 5 Mar 2020 14:22:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DF3516B0008; Thu, 5 Mar 2020 14:22:25 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C92CB6B000A; Thu, 5 Mar 2020 14:22:25 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0047.hostedemail.com [216.40.44.47]) by kanga.kvack.org (Postfix) with ESMTP id AEDFD6B0007 for ; Thu, 5 Mar 2020 14:22:25 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 700F3180AD801 for ; Thu, 5 Mar 2020 19:22:25 +0000 (UTC) X-FDA: 76562279850.13.brain88_150df4fedf54b X-HE-Tag: brain88_150df4fedf54b X-Filterd-Recvd-Size: 5360 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Mar 2020 19:22:24 +0000 (UTC) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 48YLH26gCqz9txHb; Thu, 5 Mar 2020 20:22:22 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=ASgy7a0Z; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id fd6PBkBp02eH; Thu, 5 Mar 2020 20:22:22 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 48YLH25D6Gz9txHc; Thu, 5 Mar 2020 20:22:22 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1583436142; bh=O7DpUFv/GFeL+4wPoRSCt6mdhdbvppZhJ64ANxysAUo=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=ASgy7a0ZqLkxRdb3DceHvO+mLgQKU1tMbZ07u7XCKHkkS4nXidpiHFN9k8MuwbRIE l/Q/M1sYuJlStSTJbl2Nn7+/4284wKMuasRg4hYceHY0SBe8UMVTKAog1cGcaEvmgp L9LIH9gWcqY2nIhw5m4y14tMiG9EQbEsN+cNbFlQ= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id AA4F38B880; Thu, 5 Mar 2020 20:22:22 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 0fQKJ7guOVrA; Thu, 5 Mar 2020 20:22:22 +0100 (CET) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id DF5948B87E; Thu, 5 Mar 2020 20:22:21 +0100 (CET) Subject: Re: [PATCH -next v2] powerpc/64s/pgtable: fix an undefined behaviour To: Qian Cai , mpe@ellerman.id.au, akpm@linux-foundation.org Cc: rashmicy@gmail.com, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <1583418759-16105-1-git-send-email-cai@lca.pw> From: Christophe Leroy Message-ID: Date: Thu, 5 Mar 2020 20:22:06 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <1583418759-16105-1-git-send-email-cai@lca.pw> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Le 05/03/2020 =C3=A0 15:32, Qian Cai a =C3=A9crit=C2=A0: > Booting a power9 server with hash MMU could trigger an undefined > behaviour because pud_offset(p4d, 0) will do, >=20 > 0 >> (PAGE_SHIFT:16 + PTE_INDEX_SIZE:8 + H_PMD_INDEX_SIZE:10) >=20 > Fix it by converting pud_offset() and friends to static inline > functions. I was suggesting to convert pud_index() to static inline, because that's=20 where the shift sits. Is it not possible ? Here you seems to fix the problem for now, but if someone reuses=20 pud_index() in another macro one day, the same problem may happen again. Christophe >=20 > UBSAN: shift-out-of-bounds in arch/powerpc/mm/ptdump/ptdump.c:282:15 > shift exponent 34 is too large for 32-bit type 'int' > CPU: 6 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc4-next-20200303+ #1= 3 > Call Trace: > dump_stack+0xf4/0x164 (unreliable) > ubsan_epilogue+0x18/0x78 > __ubsan_handle_shift_out_of_bounds+0x160/0x21c > walk_pagetables+0x2cc/0x700 > walk_pud at arch/powerpc/mm/ptdump/ptdump.c:282 > (inlined by) walk_pagetables at arch/powerpc/mm/ptdump/ptdump.c:311 > ptdump_check_wx+0x8c/0xf0 > mark_rodata_ro+0x48/0x80 > kernel_init+0x74/0x194 > ret_from_kernel_thread+0x5c/0x74 >=20 > Suggested-by: Christophe Leroy > Signed-off-by: Qian Cai > --- > arch/powerpc/include/asm/book3s/64/pgtable.h | 20 ++++++++++++++-----= - > 1 file changed, 14 insertions(+), 6 deletions(-) >=20 > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerp= c/include/asm/book3s/64/pgtable.h > index fa60e8594b9f..4967bc9e25e2 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > @@ -1016,12 +1016,20 @@ static inline bool p4d_access_permitted(p4d_t p= 4d, bool write) > =20 > #define pgd_offset(mm, address) ((mm)->pgd + pgd_index(address)) > =20 > -#define pud_offset(p4dp, addr) \ > - (((pud_t *) p4d_page_vaddr(*(p4dp))) + pud_index(addr)) > -#define pmd_offset(pudp,addr) \ > - (((pmd_t *) pud_page_vaddr(*(pudp))) + pmd_index(addr)) > -#define pte_offset_kernel(dir,addr) \ > - (((pte_t *) pmd_page_vaddr(*(dir))) + pte_index(addr)) > +static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address) > +{ > + return (pud_t *)p4d_page_vaddr(*p4d) + pud_index(address); > +} > + > +static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) > +{ > + return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); > +} > + > +static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long addre= ss) > +{ > + return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(address); > +} > =20 > #define pte_offset_map(dir,addr) pte_offset_kernel((dir), (addr)) > =20 >=20