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 B52C2C47081 for ; Mon, 7 Mar 2022 10:02:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239166AbiCGKDK (ORCPT ); Mon, 7 Mar 2022 05:03:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241044AbiCGJlr (ORCPT ); Mon, 7 Mar 2022 04:41:47 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E51D6D872; Mon, 7 Mar 2022 01:39:33 -0800 (PST) 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 2794860F63; Mon, 7 Mar 2022 09:39:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36D08C340E9; Mon, 7 Mar 2022 09:39:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646645972; bh=i6eWzl/jBwIItkoI0ahapdrJ09185ZksOOhX4gEGG0o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Pbyft/bXq93m406sNkEG+jwu9ljZiF+BHbqUrrwuARIGVvph7bkwi36B0uzcwCAdS OgQjWtiqB//gkCYgZ52no1651Z+Prw3ADsgMJ9ML06MvhH2fEBboYoFxz4kay1vzSS vaK8E3rmUI1JGhFuSySKdkIvfGh8akjpC64uIflE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Christopherson , syzbot+4e697fe80a31aa7efe21@syzkaller.appspotmail.com, Mike Kravetz , Paolo Bonzini , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 5.15 095/262] hugetlbfs: fix off-by-one error in hugetlb_vmdelete_list() Date: Mon, 7 Mar 2022 10:17:19 +0100 Message-Id: <20220307091705.155232526@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220307091702.378509770@linuxfoundation.org> References: <20220307091702.378509770@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson [ Upstream commit d6aba4c8e20d4d2bf65d589953f6d891c178f3a3 ] Pass "end - 1" instead of "end" when walking the interval tree in hugetlb_vmdelete_list() to fix an inclusive vs. exclusive bug. The two callers that pass a non-zero "end" treat it as exclusive, whereas the interval tree iterator expects an inclusive "last". E.g. punching a hole in a file that precisely matches the size of a single hugepage, with a vma starting right on the boundary, will result in unmap_hugepage_range() being called twice, with the second call having start==end. The off-by-one error doesn't cause functional problems as __unmap_hugepage_range() turns into a massive nop due to short-circuiting its for-loop on "address < end". But, the mmu_notifier invocations to invalid_range_{start,end}() are passed a bogus zero-sized range, which may be unexpected behavior for secondary MMUs. The bug was exposed by commit ed922739c919 ("KVM: Use interval tree to do fast hva lookup in memslots"), currently queued in the KVM tree for 5.17, which added a WARN to detect ranges with start==end. Link: https://lkml.kernel.org/r/20211228234257.1926057-1-seanjc@google.com Fixes: 1bfad99ab425 ("hugetlbfs: hugetlb_vmtruncate_list() needs to take a range to delete") Signed-off-by: Sean Christopherson Reported-by: syzbot+4e697fe80a31aa7efe21@syzkaller.appspotmail.com Reviewed-by: Mike Kravetz Cc: Paolo Bonzini Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/hugetlbfs/inode.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index cdfb1ae78a3f8..54c4e0b0dda4a 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -409,10 +409,11 @@ hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end) struct vm_area_struct *vma; /* - * end == 0 indicates that the entire range after - * start should be unmapped. + * end == 0 indicates that the entire range after start should be + * unmapped. Note, end is exclusive, whereas the interval tree takes + * an inclusive "last". */ - vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) { + vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) { unsigned long v_offset; unsigned long v_end; -- 2.34.1