From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9AAE6606A321 for ; Fri, 30 Oct 2026 11:20:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=LjJnIam+; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=X8DkNBsz DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:References:Cc:To:From:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=euk1MZglVLNri+rYCLQwY1lNbQIirnUyD9xcyB6Byp4=; b=LjJnIam+LDbdNT B1U2MgVgYjaLbVgtMJFF0PLl17tFsUA5+gAa/4eEaOvv+e1jPR8uQUjehT0gjb13zjUaQtj0aDUSE oit6f1IEvV2yK47RdhWK5RTtv9y8HRUv+bOKrwOjilv+XlHAG2JGf/Em5fkPjgc7gG0R1g7a2Yy4N HMJOtCRbPdAy5zvJf0WjRq2e5o+n59bRU/nJ/GwCQ7bx00KFxzUZerUaRBs76e5nONIZEdNYfbIfC ofyuo8KdrdZpOjdRGcP/8wRylKRF3I3E/0xJB8tyc48Qedxlm7Z49cvEdpDLIO27hpNoJ0SVTG22B mK1O30ks+HzYsK2Y8J2A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMkeU-0000000BXMT-2kGg; Fri, 30 Oct 2026 11:20:06 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMkeT-0000000BXMK-3fdO for kexec@lists.infradead.org; Fri, 30 Oct 2026 11:20:05 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 4D65E601EE; Fri, 30 Oct 2026 11:20:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C06A81F000C1; Fri, 30 Oct 2026 11:19:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793359205; bh=euk1MZglVLNri+rYCLQwY1lNbQIirnUyD9xcyB6Byp4=; h=Date:Subject:From:To:Cc:References:In-Reply-To; b=X8DkNBszymg7DuZ6+Bhdqn9pMKv5GvRX7MN6A6XfqeofSms7pCCBsQrTGdxenLipv SfBkuCgtqgHo5NAF2TLOVZP4tnKWXJLqwO+f7RPDcBuWWPWHu+PfR17rMsqBFFNV6S lPsQnD4cT7ccl6FS6w1siLPO3V4q/J5fOE8TxFzuhxio7xGSYqO+WWbeCP+mJTlFGn VTwXQGVqR5ftMB6ScKb/G3bIbPgk9qnzJpD5jp+MtS+6lx2FFbv58ZUJDcZ7IwvteO x7JhGdArobuCUeeCxdmxzteC3/LlouaJl+KZfgJJlhmQmbmIdfM/R8yr4p1n+o8BxR 1kO0q/J2vqvrw== Message-ID: <6ac05dd8-321a-4c2e-bce8-bd7ffcac9eac@kernel.org> Date: Fri, 30 Oct 2026 12:19:46 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 27/47] mm/mmu_gather: fix flushing ranges with 4 GiB or larger From: "David Hildenbrand (Arm)" To: SJ Park Cc: Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, Josef Bacik , stable@vger.kernel.org References: <20261030005726.155279-1-sj@kernel.org> <48a66134-3522-4b81-adca-4e76d52dc391@kernel.org> Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" X-Spam-Status: No, score=-12.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 10/30/26 12:15, David Hildenbrand (Arm) wrote: > On 10/30/26 01:57, SJ Park wrote: >> On Thu, 29 Oct 2026 21:33:22 +0100 "David Hildenbrand (Arm)" wrote: >> >>> From: Josef Bacik >>> >>> __tlb_adjust_range() takes the size of the range which has to be flushed >>> as an unsigned int. Its callers, tlb_flush_{pte,pmd,pud,p4d}_range(), get >>> and pass an unsigned long. Consequently, a range that is 4 GiB or larger >>> gets truncated, possibly to 0. >>> >>> On arm64 with hugetlb, a 64k kernel can have 16 GiB hugetlb folios >>> mapped contiguously at the PMD level and flush them when unmapping, and a >>> 16k kernel can flush 64 GiB PUDs through tlb_unshare_pmd_ptdesc(). So >>> at least these two scenarios are affected. >>> >>> Fix it by flushing the proper range instead of the truncated one by >>> properly using "unsigned long" for range_size. >> >> Makes sense to me. >> >>> >>> Fix generated by an LLM and sent by Josef Bacik in private. >>> >>> Fixes: b528e4b6405b ("mm/hugetlb: add tlb_remove_hugetlb_entry for handling hugetlb pages") >>> Fixes: 8ce720d5bd91 ("mm/hugetlb: fix excessive IPI broadcasts when unsharing PMD tables using mmu_gather") >>> Cc: stable@vger.kernel.org >>> Signed-off-by: Josef Bacik >>> Acked-by: Lorenzo Stoakes (ARM) >>> [ david: use two-tab indent, simplify description ] >> >> It seems the convention [1] is to put the above modification note right before >> the last S-o-b: of David. Maybe you forgot moving it after adding R-b: and >> T-b: from great reviewers? > > It's "b4 trailers" that apparently messes this up. I don't think it really > matters (some move it above all trailers), but I'll fix this up when applying. Thinking again, I *think* this order is correct. People reviewed and tested with these changes. it would be something different if I modify a patch while applying it. Because then, what people reviewed and tested would be different to the original version. -- Cheers, David