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 C84F3606A326 for ; Tue, 27 Oct 2026 09:51:08 +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=4CHCc2za; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=IK7uwDYg 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:To:References:Message-Id: Content-Transfer-Encoding:Cc:Date:In-Reply-To:From:Subject:Mime-Version: Content-Type: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=YikRuHrgcQQEQeNLoopicKeEponOUqqAXOCmGgP7bMc=; b=4CHCc2zaJsrsEJ iiS/sn6/gSSdOpJMJLi9b7XF+28l05AbyyFgKDSSTv6/pULOZk+unL3k7NT07Ys9Wb24B2q/g7PGl YpKQt6fUC71i53c/n3kZFbtJOjemZGLFI9C0aXtZlpb8roWsvQp5iDw6/zLngAkPDsl03QYp/yLiw JggLPqr50NJDJBo193w4wlKtKFE23EBxf/XYipUMTXbS7JZT3gdASm4NcdfB7OpBBEASqPA20SPqK aV3FgzPzIxEiA8VGulm31dCeistj0idFENMD6Sel383g8C1lH5Foin6khWOZTAO/15vwm0W60iAa5 iLSFcgkkxBhqRnHpS0Yw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLdpk-00000004Dr3-1x5y; Tue, 27 Oct 2026 09:51:08 +0000 Received: from out-126.mta0.migadu.com ([2001:41d0:1004:224b::7e] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLdpf-00000004Doc-1A4P for kexec@lists.infradead.org; Tue, 27 Oct 2026 09:51:04 +0000 X-Envelope-To: kexec@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=YikRuHrgcQQEQeNLoopicKeEponOUqqAXOCmGgP7bMc=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793094661; v=1; x=1793699461; b=IK7uwDYgWnddzMvKWJw3ya6jd1O95pxiSUka2B+d5LCvMVJF0eAMpUph7VCpo576csv7uSk+ RkWa1+WT24INtT8JnumhbrIqAEhPNriR3IJ5BOtfXhCFSYVDbHBk/S3Oe6w++M3F5lyKhOZXvxs 0YEaxOC7g+vVBRZSfwe0o1YE= X-Envelope-To: kexec@lists.infradead.org Received: by mta12.migadu.com with ESMTPS id 7697935976e69603; Tue, 27 Oct 2026 09:50:59 +0000 X-Mizu-Trace-ID: 7697935976e69603 X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset=us-ascii X-Archived-By: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3901.100.1.1.12\)) Subject: Re: [PATCH 26/46] mm/mmu_gather: fix flushing ranges with 4 GiB or larger From: Muchun Song In-Reply-To: <20261027-fixes_core-v1-26-6f74bec9a5bb@kernel.org> Date: Tue, 27 Oct 2026 17:50:32 +0800 Cc: Andrew Morton , 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 , 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 Content-Transfer-Encoding: quoted-printable Message-Id: <377FB184-1E61-4BF8-AC3E-33A79EC56658@linux.dev> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-26-6f74bec9a5bb@kernel.org> To: "David Hildenbrand (Arm)" X-Mailer: Apple Mail (2.3901.100.1.1.12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261027_025103_551592_281F65FE X-CRM114-Status: GOOD ( 11.59 ) X-Spam-Score: -2.1 (--) 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=-11.2 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 autolearn=unavailable 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 Oct 27, 2026, at 07:17, David Hildenbrand (Arm) = wrote: >=20 > From: Josef Bacik >=20 > __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. >=20 > On arm64 with hugetlb, a 64k kernel can flush 16 GiB hugetlb PMDs, and = a > 16k kernel can flush 64 GiB PUDs through tlb_unshare_pmd_ptdesc(). So > at least these two scenarios are affected. >=20 > Fix it by flushing the proper range instead of the truncated one. >=20 > Fix generated by an LLM and sent by Josef Bacik in private. >=20 > 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 ] > Signed-off-by: David Hildenbrand (Arm) Reviewed-by: Muchun Song Thanks.