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=-5.3 required=3.0 tests=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 7EAC4CA9EAE for ; Tue, 29 Oct 2019 20:15:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 565822067D for ; Tue, 29 Oct 2019 20:15:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726695AbfJ2UP1 (ORCPT ); Tue, 29 Oct 2019 16:15:27 -0400 Received: from mga18.intel.com ([134.134.136.126]:4073 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725840AbfJ2UP1 (ORCPT ); Tue, 29 Oct 2019 16:15:27 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Oct 2019 13:15:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,245,1569308400"; d="scan'208";a="283348320" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by orsmga001.jf.intel.com with SMTP; 29 Oct 2019 13:15:14 -0700 Received: by stinkbox (sSMTP sendmail emulation); Tue, 29 Oct 2019 22:15:13 +0200 Date: Tue, 29 Oct 2019 22:15:13 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: linux-kernel@vger.kernel.org Cc: Andrew Morton , "Kirill A. Shutemov" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , linux-mm@kvack.org Subject: khugepaged might_sleep() warn due to CONFIG_HIGHPTE=y Message-ID: <20191029201513.GG1208@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I got some khugepaged spew on a 32bit x86: [ 217.490026] BUG: sleeping function called from invalid context at include/linux/mmu_notifier.h:346 [ 217.492826] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 25, name: khugepaged [ 217.495589] INFO: lockdep is turned off. [ 217.498371] CPU: 1 PID: 25 Comm: khugepaged Not tainted 5.4.0-rc5-elk+ #206 [ 217.501233] Hardware name: System manufacturer P5Q-EM/P5Q-EM, BIOS 2203 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 Looks like it's due to CONFIG_HIGHPTE=y pte_offset_map()->kmap_atomic() vs. mmu_notifier_invalidate_range_start(). 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 :) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 0a1b4b484ac5..f05d27b7183d 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1028,12 +1028,13 @@ static void collapse_huge_page(struct mm_struct *mm, anon_vma_lock_write(vma->anon_vma); - pte = pte_offset_map(pmd, address); - pte_ptl = 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 = pte_offset_map(pmd, address); + pte_ptl = pte_lockptr(mm, pmd); + pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */ /* * After this gup_fast can't run anymore. This also removes -- Ville Syrjälä Intel