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=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,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 5D66BCA9EAE for ; Tue, 29 Oct 2019 23:15:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 16E862086A for ; Tue, 29 Oct 2019 23:15:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="SJIoiuNa" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 16E862086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A35C46B0006; Tue, 29 Oct 2019 19:15:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9BE466B0007; Tue, 29 Oct 2019 19:15:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 885926B0008; Tue, 29 Oct 2019 19:15:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0050.hostedemail.com [216.40.44.50]) by kanga.kvack.org (Postfix) with ESMTP id 61C6C6B0006 for ; Tue, 29 Oct 2019 19:15:22 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id F399D62EB for ; Tue, 29 Oct 2019 23:15:21 +0000 (UTC) X-FDA: 76098380484.21.sack03_861f0dc4f8d58 X-HE-Tag: sack03_861f0dc4f8d58 X-Filterd-Recvd-Size: 5791 Received: from mail-qt1-f194.google.com (mail-qt1-f194.google.com [209.85.160.194]) by imf38.hostedemail.com (Postfix) with ESMTP for ; Tue, 29 Oct 2019 23:15:21 +0000 (UTC) Received: by mail-qt1-f194.google.com with SMTP id x21so565839qto.12 for ; Tue, 29 Oct 2019 16:15:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=NE+Zw6qIAG29XcaEKiuhY2kMU0NwzIi72kMG/yxdslg=; b=SJIoiuNaEAHAPdZ1smUdlWpJaRFtJGmuzbGhtDcbpGsiqov181s4IdA6eE5Og4i/py F5UVdCHZX7fOdC40THhJagjcQmKuA95T4ZQjaoIVef3hOYLcqNguTTMq2u3Xl/tH2tha br1IH75nuO9MYbjiJoYOaySu9UDDgyrIdOKBoQSJ+1B6bdF9eUGeb+TUUVfKYtOCqbMV Th2bw8tyrSs8Ip3pPN/D1EvNjvglz1QJx9abISgSIrv0wIU7TU6pG7XSaA3qOhTUh99N VK/9UBMCEy5GPkMYqq2EVAoJs5FQAlmS7L7tko+HrTEWC7CbSDc1Wkf7zykv5wys3p+x 1+zg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=NE+Zw6qIAG29XcaEKiuhY2kMU0NwzIi72kMG/yxdslg=; b=l6Y/Rzg6db7w4a5JvOpZSvc+emvkmlw8lV0ZlIVIWTafaOKy8ZTiOqZxVR2PqtHsnA pPn2QCXbZBbsqnsoXS9CPSbzEw1/N14XgBA2Ds5Nu3P4XMivbGNtDDGivICbmVb5EBcA gI0zN/C82TW+EqqFFILwjtCZDRIIh+BdTjdj/MSqvw58pxN+tXe/E/8CvYGMCv/JhCW2 kwaKQFRt+ufCHp8B1iPhwuWCpefTzDy8DaBfhxk4pgLtBMtVQQymcA/DQccBDhKiToHf CDe4/5fHqStv72bVFiekJFS+YGStJNsEfIS+WN4qx3VLG4fnNiXDXFR8nqsstBbM55tp 4LwA== X-Gm-Message-State: APjAAAVJO9shPtieMZ1osBxxFSpJfHAfpn8tcIgcpZ+C+uHok4urVRr0 KUD3IO/Dkts4ZgNulDvXLqoNPg== X-Google-Smtp-Source: APXvYqyF6aACoObUpIYXhHuAaQcUgrBz2ghQqWz8+b/1UEcpT5willkQxV4mnSpXOzUzECoezZcAcw== X-Received: by 2002:ac8:5514:: with SMTP id j20mr1980574qtq.241.1572390920822; Tue, 29 Oct 2019 16:15:20 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-162-113-180.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.113.180]) by smtp.gmail.com with ESMTPSA id a5sm64362qtp.81.2019.10.29.16.15.20 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 29 Oct 2019 16:15:20 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1iPahr-0001nQ-O4; Tue, 29 Oct 2019 20:15:19 -0300 Date: Tue, 29 Oct 2019 20:15:19 -0300 From: Jason Gunthorpe To: Ville =?utf-8?B?U3lyasOkbMOk?= Cc: linux-kernel@vger.kernel.org, Andrew Morton , "Kirill A. Shutemov" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , linux-mm@kvack.org Subject: Re: khugepaged might_sleep() warn due to CONFIG_HIGHPTE=y Message-ID: <20191029231519.GJ6128@ziepe.ca> References: <20191029201513.GG1208@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191029201513.GG1208@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) 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: On Tue, Oct 29, 2019 at 10:15:13PM +0200, Ville Syrj=C3=A4l=C3=A4 wrote: > Hi, >=20 > I got some khugepaged spew on a 32bit x86: >=20 > [ 217.490026] BUG: sleeping function called from invalid context at in= clude/linux/mmu_notifier.h:346 > [ 217.492826] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2= 5, name: khugepaged > [ 217.495589] INFO: lockdep is turned off. > [ 217.498371] CPU: 1 PID: 25 Comm: khugepaged Not tainted 5.4.0-rc5-el= k+ #206 > [ 217.501233] Hardware name: System manufacturer P5Q-EM/P5Q-EM, BIOS 2= 203 07/08/2009 > [ 217.501697] Call Trace: > [ 217.501697] dump_stack+0x66/0x8e > [ 217.501697] ___might_sleep.cold.96+0x95/0xa6 > [ 217.501697] __might_sleep+0x2e/0x80 > [ 217.501697] collapse_huge_page.isra.51+0x5ac/0x1360 > [ 217.501697] ? __alloc_pages_nodemask+0xec/0xf80 > [ 217.501697] ? __alloc_pages_nodemask+0x191/0xf80 > [ 217.501697] ? trace_hardirqs_on+0x4a/0xf0 > [ 217.501697] khugepaged+0x9a9/0x20f0 > [ 217.501697] ? _raw_spin_unlock+0x21/0x30 > [ 217.501697] ? trace_hardirqs_on+0x4a/0xf0 > [ 217.501697] ? wait_woken+0xa0/0xa0 > [ 217.501697] kthread+0xf5/0x110 > [ 217.501697] ? collapse_pte_mapped_thp+0x3b0/0x3b0 > [ 217.501697] ? kthread_create_worker_on_cpu+0x20/0x20 > [ 217.501697] ret_from_fork+0x2e/0x38 >=20 > Looks like it's due to CONFIG_HIGHPTE=3Dy pte_offset_map()->kmap_atomic= () vs. > mmu_notifier_invalidate_range_start(). >=20 > My naive idea would be to just reorder those things, but not sure > if there's some magic ordering constraint here. At least the machine > still boots when I do it :) >=20 > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 0a1b4b484ac5..f05d27b7183d 100644 > +++ b/mm/khugepaged.c > @@ -1028,12 +1028,13 @@ static void collapse_huge_page(struct mm_struct= *mm, > =20 > anon_vma_lock_write(vma->anon_vma); > =20 > - pte =3D pte_offset_map(pmd, address); > - pte_ptl =3D pte_lockptr(mm, pmd); > - > mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm, > address, address + HPAGE_PMD_SIZE); > mmu_notifier_invalidate_range_start(&range); > + > + pte =3D pte_offset_map(pmd, address); > + pte_ptl =3D pte_lockptr(mm, pmd); > + Since pte and pte_ptl don't leak into invalidate_range_start this seems reasonable to me.. Good catch with the new debugging! Jason