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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> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: Mic4rYGXGkFUey_JG3J89e2oRcc-7xRwLyLl9_X3KmI_1785543412 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: 330FEA0003 X-Rspamd-Server: rspam01 X-Stat-Signature: gno6sgx18udiojw63gx4da875ynptrsh X-HE-Tag: 1785543416-9615 X-HE-Meta: U2FsdGVkX1/w6wdLPZfw2Abrw6cie5HtDUbdFd3ai+4pr9jlW10ZQ39LTiPRsNWuFAKpYJf23LUoBUjtvw803HcTx3NsRfA7tCkJgDa36yb8l87umI/fdYWvsPpRItSALnIa8H3w76rBCZuX5IB5erehlUe8CHsSdkAxf/O3DbZnsVwjb0+30MoIPZr8UaiafxxLhbSnOzubO5uXguOPnpwo1pHfbVlcFXvK5hprQOXdpssX8tHocBn5/oQT+j9et95S+NDEEalp4yaGS6MlNDVoMfbVU7AK7dzFR/0kUn3uEk+ctZQgS/JJ8Swr5i71g9Ju/XMmRLl23eOgbzNfVDFYEw2T5SQJ2xpxAQMzOoGdXLho2m9SVomXdrSUwPZUUnYvu5HbZIoGsyxIgm+UXbgx1vNwD3lAK3Q1Jr9OQgQTOp9+NaQYyQK5qppHqYmovGuUyt/MTAALlRLNe/Ce/z1hqqBs1gMyiBrhTQT08Hs2+52wodbi2vXlFfu0RqClAUty3SQa/4CkuHfPk3TeXN/WcCbBcmfqOi0D/Cda8tzQtjHaeyTBGyr11sTsE3lcAn5B67XBZHuuN0SzZZhjpGl5GOnxZLEwpiSFPW9ETW5mDJAyl6F+8Uaf2w+aNNmw32kcvkfjOFRp6qmgzLECqqNrc0zuuz0uoaUmGld6x5IDTFZeq2LugMnzTtvElM0Ve8URzy2FP5HJojdNumOJffwATfMywQH2fcuJZCKjPGWaZI8dCzO+sH0DQEV3zQSBxukQ7u8HAN/HfmW0jpSOmTPQwDcrz58QqHB9JaaRBo7xpjtqkreaSJo0RUrHqSj3l7+Szl7uIGhqO+fuYfoe6GZy39QuTiOGN/fP6dfwi52vdT11U/tmqBrloz8eZYCGCfEWdBn9Bm5fKYBPUkYwYe0ix0d7TOVw06TXNPjwDNCR8YWvQhs6U5T7cujoEJdDa6lha2+zvSwAauD+Vk7 i4T85fz8 9fg9TiZT5EFX7byGR6krCKEtqWdIdQbdbGQu4KkkcvN3J57rw19eKgag+r55DUzNbFfHLLl+BbfZfdI0SfGGCOD69YupESlAWSWaLteNHtR2PaSmSBAiSNg/almzYq09ZbRVx6mi587Hfy0HMG9xbhB5TjuPrl3Q91WJm2DlnAFxhkL/2kCFE0hb2nXom3PXBdaabF9nofxjJ4CDoYqEHVgoZVRMOBwtCfxsorfa7npiBQ5DNUsPMWpReNYUwq8S2v0SGDQs08N10rnOftzv82UeX59GWaT3JRNhuNKyCVd5PZBIxgb4s5xDWcWcZ2de1ULIk2RGy/wdFd/zBrQ1GhE190iozFlPXup8mVsK6G1k68Sb10efofMWwWBba3y+JlXBqR/SJHL4eeBQoOrsEsKj2yfnBl3YHMk1BM1fqyCM7RS/nLZNUvvv2W0bccSrqZvdWNJZWBQh12L0gxckQHGLvxOUJ7VoM8UmIKKrcVl6tNlI= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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