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X-CSE-ConnectionGUID: /GjEGPDXQfu3nZDTCbzJrg== X-CSE-MsgGUID: nW9FtGPXS/OqMx75dsWKmA== X-IronPort-AV: E=McAfee;i="6800,10657,11544"; a="58670992" X-IronPort-AV: E=Sophos;i="6.18,242,1751266800"; d="scan'208";a="58670992" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Sep 2025 13:11:16 -0700 X-CSE-ConnectionGUID: rxMXoCsLRnKz7gZkbztrzg== X-CSE-MsgGUID: FtNa1zzcTOqxP0dWgRBBbg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,242,1751266800"; d="scan'208";a="176336310" Received: from gabaabhi-mobl2.amr.corp.intel.com (HELO [10.125.110.75]) ([10.125.110.75]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Sep 2025 13:11:15 -0700 Message-ID: <04983c62-3b1d-40d4-93ae-34ca04b827e5@intel.com> Date: Fri, 5 Sep 2025 13:11:15 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 5/8] x86/mm: Use pagetable_free() To: Jason Gunthorpe , Lu Baolu Cc: Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , Jann Horn , Vasant Hegde , Alistair Popple , Peter Zijlstra , Uladzislau Rezki , Jean-Philippe Brucker , Andy Lutomirski , Yi Lai , iommu@lists.linux.dev, security@kernel.org, linux-kernel@vger.kernel.org References: <20250905055103.3821518-1-baolu.lu@linux.intel.com> <20250905055103.3821518-6-baolu.lu@linux.intel.com> <20250905184115.GQ616306@nvidia.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/5/25 11:41, Jason Gunthorpe wrote: >> --- a/arch/x86/mm/init_64.c >> +++ b/arch/x86/mm/init_64.c >> @@ -1013,7 +1013,7 @@ static void __meminit free_pagetable(struct page *page, int order) >> free_reserved_pages(page, nr_pages); >> #endif >> } else { >> - free_pages((unsigned long)page_address(page), order); >> + pagetable_free(page_ptdesc(page)); >> } >> } > Er.. So if bootmem happens to be under the table and we happen to free > it due to memory hotplug we don't go through the SVA fixing path? > > Seems wrong?? On second thought... Yes, freeing bootmem with no SVA fixing is wrong. It should be fixed. Period. But, it's wrong one time for something super rare: memory unplug of memory that was present at boot. It also can't be triggered by unprivileged users. As-is, this series fixes vfree(). That path is not nearly rare, can happen an arbitrary number of times on each boot, and might even be triggered by folks that are less than root. So I kinda think we should just make clear that this series leaves _some_ holes, but I do think it should go in mostly as-is.