# CVE-2025-21983: linux: In the Linux kernel, the following vulnerability has been resolved: mm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq... CVE-2025-21983 is fixed in 36 products on 1 platform, first by DEBIAN-CVE-2025-21983, released April 1, 2025. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2025-21983 - Priority: High - CVSS: 7.8 (high) - EPSS: 0.0020 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 1, 2025 ## Description In the Linux kernel, the following vulnerability has been resolved: mm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq Currently kvfree_rcu() APIs use a system workqueue which is "system_unbound_wq" to driver RCU machinery to reclaim a memory. Recently, it has been noted that the following kernel warning can be observed: workqueue: WQ_MEM_RECLAIM nvme-wq:nvme_scan_work is flushing !WQ_MEM_RECLAIM events_unbound:kfree_rcu_work WARNING: CPU: 21 PID: 330 at kernel/workqueue.c:3719 check_flush_dependency+0x112/0x120 Modules linked in: intel_uncore_frequency(E) intel_uncore_frequency_common(E) skx_edac(E) ... CPU: 21 UID: 0 PID: 330 Comm: kworker/u144:6 Tainted: G E 6.13.2-0_g925d379822da #1 Hardware name: Wiwynn Twin Lakes MP/Twin Lakes Passive MP, BIOS YMM20 02/01/2023 Workqueue: nvme-wq nvme_scan_work RIP: 0010:check_flush_dependency+0x112/0x120 Code: 05 9a 40 14 02 01 48 81 c6 c0 00 00 00 48 8b 50 18 48 81 c7 c0 00 00 00 48 89 f9 48 ... RSP: 0018:ffffc90000df7bd8 EFLAGS: 00010082 RAX: 000000000000006a RBX: ffffffff81622390 RCX: 0000000000000027 RDX: 00000000fffeffff RSI: 000000000057ffa8 RDI: ffff88907f960c88 RBP: 0000000000000000 R08: ffffffff83068e50 R09: 000000000002fffd R10: 0000000000000004 R11: 0000000000000000 R12: ffff8881001a4400 R13: 0000000000000000 R14: ffff88907f420fb8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88907f940000(0000) knlGS:0000000000000000 CR2: 00007f60c3001000 CR3: 000000107d010005 CR4: 00000000007726f0 PKRU: 55555554 Call Trace: ? __warn+0xa4/0x140 ? check_flush_dependency+0x112/0x120 ? report_bug+0xe1/0x140 ? check_flush_dependency+0x112/0x120 ? handle_bug+0x5e/0x90 ? exc_invalid_op+0x16/0x40 ? asm_exc_invalid_op+0x16/0x20 ? timer_recalc_next_expiry+0x190/0x190 ? check_flush_dependency+0x112/0x120 ? check_flush_dependency+0x112/0x120 __flush_work.llvm.1643880146586177030+0x174/0x2c0 flush_rcu_work+0x28/0x30 kvfree_rcu_barrier+0x12f/0x160 kmem_cache_destroy+0x18/0x120 bioset_exit+0x10c/0x150 disk_release.llvm.6740012984264378178+0x61/0xd0 device_release+0x4f/0x90 kobject_put+0x95/0x180 nvme_put_ns+0x23/0xc0 nvme_remove_invalid_namespaces+0xb3/0xd0 nvme_scan_work+0x342/0x490 process_scheduled_works+0x1a2/0x370 worker_thread+0x2ff/0x390 ? pwq_release_workfn+0x1e0/0x1e0 kthread+0xb1/0xe0 ? __kthread_parkme+0x70/0x70 ret_from_fork+0x30/0x40 ? __kthread_parkme+0x70/0x70 ret_from_fork_asm+0x11/0x20 ---[ end trace 0000000000000000 ]--- To address this switch to use of independent WQ_MEM_RECLAIM workqueue, so the rules are not violated from workqueue framework point of view. Apart of that, since kvfree_rcu() does reclaim memory it is worth to go with WQ_MEM_RECLAIM type of wq because it is designed for this purpose. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | kernel-uek ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-debug-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-doc ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-doc ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-tools ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek-tools ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-devel ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-devel ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-core ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-core ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-deprecated ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-deprecated ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-desktop ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-desktop ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra-netfilter ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-extra-netfilter ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-usb ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-usb ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-wireless ol 10 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | kernel-uek64k-modules-wireless ol 9 | 0:6.12.0-101.33.4.3.el9uek | [ELSA-2025-20480](https://patchblox.com/security/data/fix/linux/elsa-2025-20480.md) | Jul 17, 2025 | | Linux | linux Debian 13.5 (trixie) | 6.12.20-1 | [DEBIAN-CVE-2025-21983](https://patchblox.com/security/data/fix/linux/debian-cve-2025-21983.md) | Apr 1, 2025 | | Linux | linux Debian 14 | 6.12.20-1 | [DEBIAN-CVE-2025-21983](https://patchblox.com/security/data/fix/linux/debian-cve-2025-21983.md) | Apr 1, 2025 | --- Data as of 2026-11-08T19:12:23Z UTC. 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