From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 330E6262FF8; Mon, 25 May 2026 15:52:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779724357; cv=none; b=ae+COIvxiGZbXwJuVqzdwGXM/sAvP5CO9OxMFD2++anBa1vD0D9ph4nYeb4LlyiP2KqZ4A2JWRnpfv51Oa1eRRCm089Nv8F0CXRQDpXrqWBf8bu89jUF6e5usIXwv6hqNLKutvXHEZn8U7QdxSHN+zWPa3+u32pMCmEa25y8Mok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779724357; c=relaxed/simple; bh=tqbA0loR2xDZXnLKfFMuf7M2BRFAVk7486HBRiTlpok=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=heiV7MTkU2UwFyuKveT6oxFSaBK13XVODUa7Wna3zSXzqqnU+EqLPKgvVKMkSwcQSnf+vDACfZpX8FsZSfnt3hQReDn0cRPnR3e23oyvHAM2R+jSTTrhlQB4eOCCrARyAOJ8lV+c7eQvVBekU23eZV5rvuKUw95wbeJwV9UBvdc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kt3y9pvQ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kt3y9pvQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E4361F00A3A; Mon, 25 May 2026 15:52:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779724355; bh=k/Z8pdHv+cejKJRoNdNxhQU2h7dJRvk5CmidndA10Ig=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=kt3y9pvQwdSuJvSTN7r4XI5/WHegjzntVLK6Pd1S5QJhj2zIobFJYb/xhTuzCBGuL y6HSVM65kCCxp2g6iltV2ZtcmXLmgjWNXyIhIeSrZZBePRkr4YmFljRJTEFEbDlS9A a8y584fH//yWR59AYHGGrQnzb54Z2e+VZIaSZAiax5tru2UysZVas7oSUfj3vgtXMp LEpkO6WnIGt0K2FEOaHaiwSZqYLaMbnrv0rYf299gs55+VqF/Xi9wKg8P39V4ZATqj oJ2TY32irf0jqG+n64y3WOujqj5K4rEnmANxrZPN9Ag0MGo2cJOz6YvYLkpXevOawy zNIPOEAhm4E4A== Received: from phl-compute-01.internal (phl-compute-01.internal [10.202.2.41]) by mailfauth.phl.internal (Postfix) with ESMTP id AF47EF40068; Mon, 25 May 2026 11:52:34 -0400 (EDT) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-01.internal (MEProxy); Mon, 25 May 2026 11:52:34 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTFG3QYNTvlQv4dXNCn1oodIpGtSg2/FSbVjxuVpQ1UyDWtTeK1CyeqKqmJVajGwCO wIChQ7Vt+BXUskOWr6LlBPn5GN5fGeqIk/NYKTa7qGi7goriiLHEOgMdCN04mw+FZtqYdg XErwWFDznvfyjghz9mVLXKWox2GcuQMRU36tAor3BJtQgbKRAsNYDSm4IMOLEaZpCmNrZV 1Azo9HmUZBLZ/jpte6sWbkMoMVQmjwnZysrX/e7xS+6iJOK1SGB1tZpM2eqpHr33IvrFjz GsC6d4gEejnCFMPKdLRWBwAG+EL3MQw/6/7pdlGjdNgxTKKiFHLJw02Nwa/LaqI65l03Tk W43i4GsczMkIPAnVOQktTyqvrTxNqlwhagFQqla8GI6lpovjMMG6yECuWIAupScgIhjeC0 RPhDVRC4U1j/Q+x/9dF+fCmWjXKdI24pKDdslMjuFe5Angg4dk1J53w2TudjkLs1mBIyc3 tDx4SDYb8Ed29GaGAQcMvjGGE+ZHk3dW6BEPZkEXLOyABIBm32uBzaVDaR02mRitIGSm1S cvzCpK7BEJwsMlBGMO+0PNhsvyNG5fBxc2MVprZ1HOo27C3yMO08eLPPgoH/8bAy7ImtTr Sluo4QhynIVqoTPRd6qxnBH5FWbYIClaoSGfgY87TMP3ibV2pyiFBkRx9gBg X-ME-Proxy: Feedback-ID: i10464835:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Mon, 25 May 2026 11:52:32 -0400 (EDT) Date: Mon, 25 May 2026 16:52:27 +0100 From: Kiryl Shutsemau To: Muchun Song Cc: Muchun Song , Oscar Salvador , Andrew Morton , David Hildenbrand , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] mm/hugetlb_vmemmap: fix incorrect vmemmap restore in rollback Message-ID: References: <20260525025213.2229628-1-songmuchun@bytedance.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260525025213.2229628-1-songmuchun@bytedance.com> On Mon, May 25, 2026 at 10:52:13AM +0800, Muchun Song wrote: > vmemmap_restore_pte() rebuilds restored vmemmap pages from a > tail-page template derived from compound_head(). This is wrong when the > current PTE already maps a page whose contents are not tail-page > metadata. > > In the rollback path of vmemmap_remap_free(), the first restored PTE is > backed by vmemmap_head and contains head-page metadata. Reconstructing > that page from a tail-page template overwrites the head-page state and > corrupts the restored vmemmap page. > > Fix this by copying the full page from the page currently mapped by the > PTE. Also pass vmemmap_tail to the rollback walk so only PTEs backed by > the shared tail page are restored, while the head PTE remains mapped to > vmemmap_head. Add VM_WARN_ON_ONCE() checks for unexpected cases. > > Fixes: c0b495b91a47 ("mm/hugetlb: refactor code around vmemmap_walk") > Cc: stable@vger.kernel.org > Signed-off-by: Muchun Song Acked-by: Kiryl Shutsemau Thanks! -- Kiryl Shutsemau / Kirill A. Shutemov