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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B8B1E784AC for ; Mon, 2 Oct 2023 13:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237333AbjJBNNy convert rfc822-to-8bit (ORCPT ); Mon, 2 Oct 2023 09:13:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53076 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236163AbjJBNNw (ORCPT ); Mon, 2 Oct 2023 09:13:52 -0400 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A42C493 for ; Mon, 2 Oct 2023 06:13:49 -0700 (PDT) Received: from imladris.home.surriel.com ([10.0.13.28] helo=imladris.surriel.com) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qnIjv-00088s-2O; Mon, 02 Oct 2023 09:13:35 -0400 Message-ID: <5c6c554ad749531826e71083f56cde90f336942a.camel@surriel.com> Subject: Re: [PATCH 2/3] hugetlbfs: close race between MADV_DONTNEED and page fault From: Rik van Riel To: Mike Kravetz Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, linux-mm@kvack.org, akpm@linux-foundation.org, muchun.song@linux.dev, leit@meta.com, willy@infradead.org Date: Mon, 02 Oct 2023 09:13:35 -0400 In-Reply-To: <20231002043958.GB11194@monkey> References: <20231001005659.2185316-1-riel@surriel.com> <20231001005659.2185316-3-riel@surriel.com> <20231002043958.GB11194@monkey> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.46.4 (3.46.4-1.fc37) MIME-Version: 1.0 Sender: riel@surriel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2023-10-01 at 21:39 -0700, Mike Kravetz wrote: > > Looks like vma->vm_file is NULL and __hugetlb_zap_begin is trying to > do > i_mmap_lock_write(vma->vm_file->f_mapping). > > Guess I did look closely. :) Ugh. It looks like the fix for this bug ended up getting pulled into patch 3, instead of patch 2. I've had it in my code for a while now :/ Let me move the fix for this thing into patch 2. void __hugetlb_zap_begin(struct vm_area_struct *vma, unsigned long *start, unsigned long *end) { adjust_range_if_pmd_sharing_possible(vma, start, end); hugetlb_vma_lock_write(vma); if (vma->vm_file) i_mmap_lock_write(vma->vm_file->f_mapping); } -- All Rights Reversed.