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 7D041C77B73 for ; Mon, 24 Apr 2023 13:33:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232445AbjDXNd0 (ORCPT ); Mon, 24 Apr 2023 09:33:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232480AbjDXNdF (ORCPT ); Mon, 24 Apr 2023 09:33:05 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4C127EEF for ; Mon, 24 Apr 2023 06:32:47 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0124962372 for ; Mon, 24 Apr 2023 13:32:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E83EC4339B; Mon, 24 Apr 2023 13:32:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1682343143; bh=7HQpbArraXO722c7LsNvEPYtRBg/Il/qB6GVgKIof3E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1ruLE+yQnCBXOmMDLYQQkYN4yKnSV4wBX/LzN1jiC8p6buywD2FPHn9+vGXx2eznd 4R0COVEW9bjI/LSomSXtbQz/YKDGK+IXlGrbUE7Pcpb1k6HZoPZhzaCAvfu57mQBMs VNFNVQEJXPlMRukGyWH0MFN/t432Bl6k6OnoEffM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Liam R. Howlett" , Rick Edgecombe , Andrew Morton Subject: [PATCH 6.2 092/110] mm/mmap: regression fix for unmapped_area{_topdown} Date: Mon, 24 Apr 2023 15:17:54 +0200 Message-Id: <20230424131139.988604476@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230424131136.142490414@linuxfoundation.org> References: <20230424131136.142490414@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Liam R. Howlett commit 58c5d0d6d522112577c7eeb71d382ea642ed7be4 upstream. The maple tree limits the gap returned to a window that specifically fits what was asked. This may not be optimal in the case of switching search directions or a gap that does not satisfy the requested space for other reasons. Fix the search by retrying the operation and limiting the search window in the rare occasion that a conflict occurs. Link: https://lkml.kernel.org/r/20230414185919.4175572-1-Liam.Howlett@oracle.com Fixes: 3499a13168da ("mm/mmap: use maple tree for unmapped_area{_topdown}") Signed-off-by: Liam R. Howlett Reported-by: Rick Edgecombe Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/mmap.c | 48 +++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 43 insertions(+), 5 deletions(-) --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1565,7 +1565,8 @@ static inline int accountable_mapping(st */ static unsigned long unmapped_area(struct vm_unmapped_area_info *info) { - unsigned long length, gap; + unsigned long length, gap, low_limit; + struct vm_area_struct *tmp; MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); @@ -1574,12 +1575,29 @@ static unsigned long unmapped_area(struc if (length < info->length) return -ENOMEM; - if (mas_empty_area(&mas, info->low_limit, info->high_limit - 1, - length)) + low_limit = info->low_limit; +retry: + if (mas_empty_area(&mas, low_limit, info->high_limit - 1, length)) return -ENOMEM; gap = mas.index; gap += (info->align_offset - gap) & info->align_mask; + tmp = mas_next(&mas, ULONG_MAX); + if (tmp && (tmp->vm_flags & VM_GROWSDOWN)) { /* Avoid prev check if possible */ + if (vm_start_gap(tmp) < gap + length - 1) { + low_limit = tmp->vm_end; + mas_reset(&mas); + goto retry; + } + } else { + tmp = mas_prev(&mas, 0); + if (tmp && vm_end_gap(tmp) > gap) { + low_limit = vm_end_gap(tmp); + mas_reset(&mas); + goto retry; + } + } + return gap; } @@ -1595,7 +1613,8 @@ static unsigned long unmapped_area(struc */ static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) { - unsigned long length, gap; + unsigned long length, gap, high_limit, gap_end; + struct vm_area_struct *tmp; MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); /* Adjust search length to account for worst case alignment overhead */ @@ -1603,12 +1622,31 @@ static unsigned long unmapped_area_topdo if (length < info->length) return -ENOMEM; - if (mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1, + high_limit = info->high_limit; +retry: + if (mas_empty_area_rev(&mas, info->low_limit, high_limit - 1, length)) return -ENOMEM; gap = mas.last + 1 - info->length; gap -= (gap - info->align_offset) & info->align_mask; + gap_end = mas.last; + tmp = mas_next(&mas, ULONG_MAX); + if (tmp && (tmp->vm_flags & VM_GROWSDOWN)) { /* Avoid prev check if possible */ + if (vm_start_gap(tmp) <= gap_end) { + high_limit = vm_start_gap(tmp); + mas_reset(&mas); + goto retry; + } + } else { + tmp = mas_prev(&mas, 0); + if (tmp && vm_end_gap(tmp) > gap) { + high_limit = tmp->vm_start; + mas_reset(&mas); + goto retry; + } + } + return gap; }