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 EE0FA26159E; Fri, 17 Jul 2026 09:09:17 +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=1784279359; cv=none; b=Akahk2YiXMKjoj96ojoQH8QlbJYUeaTD/StkM8BkNm3CO6TORzHNBRcLz+KmVvx4Yv1Jjh24o6VosM9J2WibuaXa6XK8iWn+j9TlQQMreEJiIpZXufdpWCKbguDzZnS+bdqKv6i86YA3JgeIwkHkE9jtuVAsb2tKtWQ7Pu2xcbY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784279359; c=relaxed/simple; bh=SdL7vaie1iVm0Uqsd+hSgCyngPIokN0XTUTmdLokKik=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=j7MmKGDVbdIeMp/tNTQnI1SUNK7Fnl5Rn41wO2gixdk0JVbDPAG+DEG+lCy9/puQfcLnHGXihyTlXvQmTguA/jEfyPHS1S7bYjXFYdgtwMupUM7qxzawVtyOBKAEVkdn1/49M/c7TWpu8EBAdvZF5azzxxmxg0NRzZrvq2XAqes= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CTNM/OUs; 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="CTNM/OUs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1AC11F00A3D; Fri, 17 Jul 2026 09:09:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784279357; bh=8hDLGVnRCVJmvr3vYWUVHX9dK81AR2oabc5yMqDGpv8=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=CTNM/OUs7WYBRthOa7sxeviy2ss9V2NMHXfSI40iKlYwStGfZv0236M7i1D/6DpA8 ddP50XPK2ArCklwcuxf1OYLH6bUJMcke39mX8yxQCat4gzUWtjtnES4a8MvewcXKwh hiCevr25HkWNe8xZLPRv1oBaDbrGNn/OOsZuBJQlt5Nl5kfmkCLA4DyVpzvP8yPI/E 5qs+Ga4y1Ta+VG/wDzcG5KboczyH3trGbDDn0eGsx2jQYaEzfAx/6g69dlYTsRzG/U 0LgErA/GtRghM+ZJ5sjCvY2HR2nwWTzzKuqwQbPCfNWOg3C6LwbPmO5zq18Pvesop3 5qdpqxkusrsvQ== Message-ID: <3f10acf9-5441-4f77-a93b-31552d7eb706@kernel.org> Date: Fri, 17 Jul 2026 11:09:13 +0200 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 v2 1/2] mm/page_reporting: use system_freezable_wq to fix UAF during suspend To: Link Lin , Andrew Morton , Vlastimil Babka , "Michael S . Tsirkin" Cc: virtualization@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, prasin@google.com, rientjes@google.com, duenwen@google.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, Ammar Faizi , jiaqiyan@google.com, ahwilkins@google.com, Greg Thelen , Alexander Duyck , jthoughton@google.com, stable@vger.kernel.org References: <20260717002311.681748-1-linkl@google.com> <20260717002311.681748-2-linkl@google.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260717002311.681748-2-linkl@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/17/26 02:22, Link Lin wrote: > During PM freeze (e.g. S3 suspend or S4 hibernation), device drivers like > virtio_balloon reset their underlying virtio devices and delete their > virtqueues via vdev->config->del_vqs(). > > However, page reporting work (page_reporting_process) was scheduled on > the global system_wq. Because system_wq lacks the WQ_FREEZABLE flag, the > PM freezer skips it, leaving page_reporting_process active during > suspend. If pages are freed into the buddy allocator while suspending, > page reporting invokes virtballoon_free_page_report() on deleted > virtqueues: > > [ 196.795226] general protection fault, probably for non-canonical address 0xaa1436fe70dae6df: 0000 [#1] SMP NOPTI > [ 196.825967] Workqueue: events page_reporting_process > [ 196.831038] RIP: 0010:virtqueue_add_split+0x233/0x4c0 [virtio_ring] > [ 196.927073] virtballoon_free_page_report+0x3a/0xe0 [virtio_balloon] > [ 196.946943] page_reporting_process+0x370/0x4f0 > > Fix this by switching page reporting work to system_freezable_wq. This > ensures that the PM freezer pauses page_reporting_process before device > drivers destroy their reporting virtqueues. > > This aligns with the driver's existing design. The comment in > virtballoon_freeze() states: > /* > * The workqueue is already frozen by the PM core before this > * function is called. > */ > > Suggested-by: David Hildenbrand > Suggested-by: Michael S. Tsirkin > Acked-by: David Rientjes > Fixes: 924a663f75e2 ("virtio-balloon: Reporting free page reservations") > Cc: stable@vger.kernel.org > Signed-off-by: Link Lin Acked-by: David Hildenbrand (Arm) -- Cheers, David