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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 CEEACC3A59F for ; Mon, 26 Aug 2019 17:30:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 97DCC20874 for ; Mon, 26 Aug 2019 17:30:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="aLr5JbFy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 97DCC20874 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 249E26B05C5; Mon, 26 Aug 2019 13:30:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1D2DA6B05C9; Mon, 26 Aug 2019 13:30:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 09A266B05CA; Mon, 26 Aug 2019 13:30:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0040.hostedemail.com [216.40.44.40]) by kanga.kvack.org (Postfix) with ESMTP id D73F16B05C5 for ; Mon, 26 Aug 2019 13:30:49 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 83A51181AC9AE for ; Mon, 26 Aug 2019 17:30:49 +0000 (UTC) X-FDA: 75865269018.03.car64_5e69ea8a74750 X-HE-Tag: car64_5e69ea8a74750 X-Filterd-Recvd-Size: 4615 Received: from hqemgate15.nvidia.com (hqemgate15.nvidia.com [216.228.121.64]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Mon, 26 Aug 2019 17:30:48 +0000 (UTC) Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Mon, 26 Aug 2019 10:30:48 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Mon, 26 Aug 2019 10:30:47 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Mon, 26 Aug 2019 10:30:47 -0700 Received: from rcampbell-dev.nvidia.com (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 26 Aug 2019 17:30:46 +0000 Subject: Re: [PATCH] mm/migrate: initialize pud_entry in migrate_vma() To: Vlastimil Babka , CC: , , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Andrew Morton References: <20190719233225.12243-1-rcampbell@nvidia.com> <0d639edf-9f96-c170-4920-d64c2891d35d@suse.cz> X-Nvconfidentiality: public From: Ralph Campbell Message-ID: Date: Mon, 26 Aug 2019 10:30:46 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <0d639edf-9f96-c170-4920-d64c2891d35d@suse.cz> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1566840648; bh=wgJD6Csy/s6yr4UYxieJmYbxqUj/d5mbZ6ONdDZ3WhI=; h=X-PGP-Universal:Subject:To:CC:References:X-Nvconfidentiality:From: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=aLr5JbFymgRG9vRzfe1Hbp8+2BZTFtY3t76OzLIP/HV/mKdZMv0dk32Dopf8kv8Mf I+2RnPrashuxzsKe5d1FnGYg2LOfele0EkIwTR2oO3orHb0fHC8RLRhxknZ1d0e+b3 f/2Wvm2zEzppEMeE2AXrz/MKsv40syocN2kkWTJzszN7ZVL6rfKoWD9/eOBb2i2GSL JPnrXWl+DT0LO9nYpoKT7pbyVgtEH+5HcMl5VwDXY3V89x4IyZC/HDyVGnNxWVHqu/ YBuiO2c9y0J7uyZPIzSGUTdodU/os6UGzZXKG3UGaQ7asTj3p4P1KUFOUlX2M+EveK ED/Jpu20djarQ== 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: On 8/26/19 8:11 AM, Vlastimil Babka wrote: > On 7/20/19 1:32 AM, Ralph Campbell wrote: >> When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls >> migrate_vma_collect() which initializes a struct mm_walk but >> didn't initialize mm_walk.pud_entry. (Found by code inspection) >> Use a C structure initialization to make sure it is set to NULL. >> >> Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use w= ith >> device memory") >> Cc: stable@vger.kernel.org >> Signed-off-by: Ralph Campbell >> Cc: "J=C3=A9r=C3=B4me Glisse" >> Cc: Andrew Morton >=20 > So this bug can manifest by some garbage address on stack being called, r= ight? I > wonder, how comes it didn't actually happen yet? Right. Probably because HMM isn't widely being used in production yet. >=20 >> --- >> mm/migrate.c | 17 +++++++---------- >> 1 file changed, 7 insertions(+), 10 deletions(-) >> >> diff --git a/mm/migrate.c b/mm/migrate.c >> index 515718392b24..a42858d8e00b 100644 >> --- a/mm/migrate.c >> +++ b/mm/migrate.c >> @@ -2340,16 +2340,13 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, >> static void migrate_vma_collect(struct migrate_vma *migrate) >> { >> struct mmu_notifier_range range; >> - struct mm_walk mm_walk; >> - >> - mm_walk.pmd_entry =3D migrate_vma_collect_pmd; >> - mm_walk.pte_entry =3D NULL; >> - mm_walk.pte_hole =3D migrate_vma_collect_hole; >> - mm_walk.hugetlb_entry =3D NULL; >> - mm_walk.test_walk =3D NULL; >> - mm_walk.vma =3D migrate->vma; >> - mm_walk.mm =3D migrate->vma->vm_mm; >> - mm_walk.private =3D migrate; >> + struct mm_walk mm_walk =3D { >> + .pmd_entry =3D migrate_vma_collect_pmd, >> + .pte_hole =3D migrate_vma_collect_hole, >> + .vma =3D migrate->vma, >> + .mm =3D migrate->vma->vm_mm, >> + .private =3D migrate, >> + }; >> =20 >> mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm_walk.mm= , >> migrate->start, >> >=20