{"id":"CVE-2026-80916","summary":"kcov: fix data corruption and race conditions on PREEMPT_RT","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nkcov: fix data corruption and race conditions on PREEMPT_RT\n\nsyzbot is reporting KCOV state corruption on PREEMPT_RT kernels, for the\ntemporary storage used for saving/restoring remote KCOV state is currently\nallocated as the per-CPU area.\n\nOn PREEMPT_RT kernels, softirq handlers run as preemptible task threads\n(e.g., ksoftirqd). If a softirq context preempts a task running a remote\nKCOV session, it safely saves the task's state into the per-CPU area.\nHowever, if that softirq thread is subsequently preempted by a higher-\npriority softirq thread on the same CPU, the second softirq will overwrite\nthe same per-CPU area, permanently destroying the original task's KCOV\nstate.\n\nFix this data corruption by moving the temporary storage from the per-CPU\narea to the per-thread area. Since each softirq thread now owns its own\ntask context, nested softirq preemption no longer causes data overwrites.\n\nNote that while the temporary storage is now on a per-thread basis, the\nper-CPU kcov_percpu_data.lock must be retained, for we need to ensure that\nkcov_remote_start() and kcov_remote_stop() operate atomically without\nracing against asynchronous interrupts that manipulate the current task's\nKCOV state.\n\nIt is likely that GFP_KERNEL allocation by vmalloc_node() in kcov_init()\nhas already called panic() before returning NULL, for there will be no\nOOM-killable userspace processes when __init function of built-in module\nruns. But this patch also fixes crashing the kernel when vmalloc_node()\nin kcov_init() returned NULL, for kcov_init() left per-CPU irq_area == NULL\nbut kcov_remote_start() depends on per-CPU irq_area != NULL, resulting in\n\n  (1) doing vmalloc() in kcov_remote_start() despite !in_task() context\n\n  (2) out-of-array-bounds access if (1) succeeded but\n      kcov-\u003eremote_size \u003c CONFIG_KCOV_IRQ_AREA_SIZE\n\n  (3) always leak memory allocated by (1), eventually killing all\n      OOM-killable userspace processes\n\nproblems.","modified":"2026-09-11T03:49:00.257121930Z","published":"2026-09-09T16:13:14.587Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80916.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/18799e858b407bf355383c9dd6c06477aa437134"},{"type":"WEB","url":"https://git.kernel.org/stable/c/22670d1552fe155822b2abf91f920925f7d067b4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5dc59fc959b2b5742985d7ef24bccd1868217dc2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8ed3ddf23d39bf5338406bd9f8863d44748cf6ce"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a2fb8222cde23b0001812ed3acb7c0ea36dd94e2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e11f5b48c82703242a3be7a7ae4b4940b4cb4610"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ef7048d8a614c5f5a9b20513a5428101a744514e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f8c9a3ec36b4ee3d4701b9be08f40e7bfbf89761"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80916.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80916"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5ff3b30ab57da82d8db4f14662a2858cabfbc2c0"},{"fixed":"ef7048d8a614c5f5a9b20513a5428101a744514e"},{"fixed":"8ed3ddf23d39bf5338406bd9f8863d44748cf6ce"},{"fixed":"5dc59fc959b2b5742985d7ef24bccd1868217dc2"},{"fixed":"a2fb8222cde23b0001812ed3acb7c0ea36dd94e2"},{"fixed":"18799e858b407bf355383c9dd6c06477aa437134"},{"fixed":"e11f5b48c82703242a3be7a7ae4b4940b4cb4610"},{"fixed":"22670d1552fe155822b2abf91f920925f7d067b4"},{"fixed":"f8c9a3ec36b4ee3d4701b9be08f40e7bfbf89761"},{"fixed":"2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80916.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.8.0"},{"fixed":"5.10.269"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.220"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.185"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.154"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.106"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.47"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.11"}]},{"type":"ECOSYSTEM","events":[{"introduced":"7.2.0"},{"fixed":"7.2.1"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80916.json"}}],"schema_version":"1.9.0"}