{"cve":"CVE-2026-80719","nvd":{"published":"2026-08-28T08:16:57.720","modified":"2026-08-28T08:16:57.720","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: mglru: fix stale batch updates after memcg reparenting\n\nThe mglru page table walker batches per-generation size deltas in\nwalk->nr_pages while walking page tables without holding the lruvec lock. \nThe reset_batch_size() later folds those deltas into walk->lruvec under\nthe lruvec lock.\n\nThe page table walker can run concurrently with the memcg reparenting path\nas follows:\n\nCPU0                           CPU1\n====                           ====\n\nwalk_mm\n--> walk_page_range\n    --> update_batch_size\n        --> walk->nr_pages += delta\n\n                              mem_cgroup_css_offline\n                              --> memcg_reparent_objcgs\n                                  --> lock lruvec\n                                      lru_gen_reparent_memcg\n                                      --> reparent child folios to parent\n                                      unlock lruvec\n\n    lock lruvec\n    reset_batch_size\n    --> child lrugen->nr_pages += delta\n\nThis will trigger the following warning in lru_gen_exit_memcg():\n\n\tVM_WARN_ON_ONCE(memchr_inv(lruvec->lrugen.nr_pages, 0,\n\t\t\t\t   sizeof(lruvec->lrugen.nr_pages)));\n\nAnd the user-visible impact of underestimated nr_pages in MGLRU was\npremature OOMs because MGLRU does not try to reclaim memory when nr_pages\nreaches zero, but there are still more pages.\n\nTo fix it, make reset_batch_size() check CSS_DYING under RCU before\nflushing the pending batch.  A non-dying memcg keeps the original lruvec\nstable against RCU-delayed offlining; a dying memcg redirects the deltas\nto the first non-dying ancestor.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/de4660898b7aa7e03d3b120a6bfa6b26211e4e77","https://git.kernel.org/stable/c/fceb6b7f3ddec6ea9fc11577f4cf1b2da73a3101"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:50.842544443+00:00"},"epss":{"cve":"CVE-2026-80719","score":0.00198,"percentile":0.09548,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}