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 A4674606A31A for ; Fri, 30 Oct 2026 23:57:55 +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=x9fkHCHJ; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=H92dZjxo 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: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=yYH3ZHoy3wMBa62rdRKFlOT5iUEACgCaryz4Ge7v3YA=; b=x9fkHCHJ/C275d 5UCLvQBLcg6khBKa7hAgD7T1ohfbtdM3IdGt4hR58OOoDZwjRv47vJLxZw7ze7Fu/FRThl+soXGIG 2q8M2c2B5LGxU9g/UGGXARXfIo9Io/fwSJiOxZPVy5jJFReAbu/g7Z6tWM7lfsbG2xz+ACKbsatIc vhPboeGZy9UMRPoXjmFiayCQgXhfks+QZYZZtZ7WeTgI6XtqW27/9/V8H62FvmUJO4qmyqTVN1blV QJPWO2SSe/V2Op7jPcHDfh5MK8KTFDQdN7S9mkDTtDMrw01Mac6nv98h4IKAU/Ak4YmqR37lnjUmr u+Ol4B6NsUZVy2hPu77w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMwTp-0000000Ckxv-2nsB; Fri, 30 Oct 2026 23:57:53 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMwTo-0000000Ckxo-0DOe for kexec@lists.infradead.org; Fri, 30 Oct 2026 23:57:52 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 1F46E43CF9; Fri, 30 Oct 2026 23:57:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC0D51F000C1; Fri, 30 Oct 2026 23:57:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793404671; bh=yYH3ZHoy3wMBa62rdRKFlOT5iUEACgCaryz4Ge7v3YA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=H92dZjxoEBjeg93MdfYqW/6IAuzONdaBmZ/OVUIsM/rdieejBoUuPSaLoOlo/X9o1 LlUIR8KOWVCHXQJ0RXY6QJvgcTFZDjQ/SKuYB5lMYKKlKkip+akHrFT7sXCC+QTS8t cXMzHeO+7K/QXNLgWd24gdJG0IuXHSKRDFzXJJyx+460C2uW4fEZiprWvkS9p5Z/xm XcsKKOfRK6ab+J2juDoX2gfEAAT5ljzSTYck93sZyWI7z36GkDg4BEq9Fni2WcB9aI mjhqPrj/7BdZ6vAmuIqFRM5iI7AFLcUsJ30+CpY1jeLBqohnWPf9I1ONGO9xBX9uKC DGSaHM1C+gE2w== From: SJ Park To: "David Hildenbrand (Arm)" Cc: SJ Park , 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 Subject: Re: [PATCH v2 27/47] mm/mmu_gather: fix flushing ranges with 4 GiB or larger Date: Fri, 30 Oct 2026 16:57:41 -0700 Message-ID: <20261030235742.87036-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <6ac05dd8-321a-4c2e-bce8-bd7ffcac9eac@kernel.org> References: X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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=-13.9 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_GIT 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 Fri, 30 Oct 2026 12:19:46 +0100 "David Hildenbrand (Arm)" wrote: > 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. Makes sense to me. Thank you for the kind clarification! Thanks, SJ [...]