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[94.66.118.61]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47fd45a0c8bsm10836910f8f.34.2026.07.31.17.16.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jul 2026 17:16:51 -0700 (PDT) Date: Fri, 31 Jul 2026 20:16:47 -0400 From: "Michael S. Tsirkin" To: Link Lin Cc: Andrew Morton , Vlastimil Babka , David Hildenbrand , 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 Subject: Re: [PATCH v3] mm/page_reporting: use system_freezable_wq to fix UAF during suspend Message-ID: <20260731201559-mutt-send-email-mst@kernel.org> References: <20260721005603.1710551-1-linkl@google.com> <20260722173639.34d3f58413354218b24a5b0d@linux-foundation.org> <20260723051327-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Jul 31, 2026 at 01:21:40PM -0700, Link Lin wrote: > On Thu, Jul 23, 2026 at 2:15 AM Michael S. Tsirkin wrote: > > > > I suspect rest of work items we have, e.g. update_balloon_stats_work/update_balloon_size_work > > all have issues around freeze/restore and error handling. > > > > -- > > MST > > > > Hi Michael, > > We have indeed discovered a kernel crash in update_balloon_stats_work > after the balloon driver failed to resume and initialize in our > production fleet. > > Alex Wilkins diagnosed, root caused, and > reported this vulnerability. I wouldn't call this a "vulnerability" just a garden variety bug. > I am currently drafting and testing a > 2-patch series to gracefully unregister callbacks and cancel work > items on resume failure so that the VM continues running without the > balloon driver instead of crashing with a kernel panic. > > I wanted to follow up and let you know that we are actively working on > this. I will send out the patches to the list as soon as they are > sufficiently tested. > > Best, > Link