{"id":"CVE-2023-53522","title":"cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ncgroup,freezer: hold cpu_hotplug_lock before freezer_mutex\n\nsyzbot is reporting circular locking dependency between cpu_hotplug_lock\nand freezer_mutex, for commit f5d39…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= f5d39b020809146cc28e6e73369bf8065e0310aa < 3756171b97c307d9df8b8ded1d883eec30172085","Linux >= f5d39b020809146cc28e6e73369bf8065e0310aa < 34fbb7b45bae20b551dda24337c7761ca13ce69d","Linux >= f5d39b020809146cc28e6e73369bf8065e0310aa < 57dcd64c7e036299ef526b400a8d12b8a2352f26","Linux 6.1"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-05T20:23:05.576126Z"},"published":"2025-10-01","updated":"2026-11-05","sourceUpdated":"2026-11-05T20:31:13.300Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-53522","references":[{"url":"https://git.kernel.org/stable/c/3756171b97c307d9df8b8ded1d883eec30172085"},{"url":"https://git.kernel.org/stable/c/34fbb7b45bae20b551dda24337c7761ca13ce69d"},{"url":"https://git.kernel.org/stable/c/57dcd64c7e036299ef526b400a8d12b8a2352f26"}],"tags":["cve.org"],"epss":0.00154,"epssPercentile":0.0459,"ingestedAt":"2026-11-05T22:38:31.806Z","slug":"CVE-2023-53522","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ncgroup,freezer: hold cpu_hotplug_lock before freezer_mutex\n\nsyzbot is reporting circular locking dependency between cpu_hotplug_lock\nand freezer_mutex, for commit f5d39b020809 (\"freezer,sched: Rewrite core\nfreezer logic\") replaced atomic_inc() in freezer_apply_state() with\nstatic_branch_inc() which holds cpu_hotplug_lock.\n\ncpu_hotplug_lock => cgroup_threadgroup_rwsem => freezer_mutex\n\n  cgroup_file_write() {\n    cgroup_procs_write() {\n      __cgroup_procs_write() {\n        cgroup_procs_write_start() {\n          cgroup_attach_lock() {\n            cpus_read_lock() {\n              percpu_down_read(&cpu_hotplug_lock);\n            }\n            percpu_down_write(&cgroup_threadgroup_rwsem);\n          }\n        }\n        cgroup_attach_task() {\n          cgroup_migrate() {\n            cgroup_migrate_execute() {\n              freezer_attach() {\n                mutex_lock(&freezer_mutex);\n                (...snipped...)\n              }\n            }\n          }\n        }\n        (...snipped...)\n      }\n    }\n  }\n\nfreezer_mutex => cpu_hotplug_lock\n\n  cgroup_file_write() {\n    freezer_write() {\n      freezer_change_state() {\n        mutex_lock(&freezer_mutex);\n        freezer_apply_state() {\n          static_branch_inc(&freezer_active) {\n            static_key_slow_inc() {\n              cpus_read_lock();\n              static_key_slow_inc_cpuslocked();\n              cpus_read_unlock();\n            }\n          }\n        }\n        mutex_unlock(&freezer_mutex);\n      }\n    }\n  }\n\nSwap locking order by moving cpus_read_lock() in freezer_apply_state()\nto before mutex_lock(&freezer_mutex) in freezer_change_state().\n\n## Affected\n\n- `Linux >= f5d39b020809146cc28e6e73369bf8065e0310aa < 3756171b97c307d9df8b8ded1d883eec30172085`\n- `Linux >= f5d39b020809146cc28e6e73369bf8065e0310aa < 34fbb7b45bae20b551dda24337c7761ca13ce69d`\n- `Linux >= f5d39b020809146cc28e6e73369bf8065e0310aa < 57dcd64c7e036299ef526b400a8d12b8a2352f26`\n- `Linux 6.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}