CVE-2026-43229

Published May 6, 2026

Last updated 6 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: media: chips-media: wave5: Fix device cleanup order to prevent kernel panic Move video device unregistration to the beginning of the remove function to ensure all video operations are stopped before cleaning up the worker thread and disabling PM runtime. This prevents hardware register access after the device has been powered down. In polling mode, the hrtimer periodically triggers wave5_vpu_timer_callback() which queues work to the kthread worker. The worker executes wave5_vpu_irq_work_fn() which reads hardware registers via wave5_vdi_read_register(). The original cleanup order disabled PM runtime and powered down hardware before unregistering video devices. When autosuspend triggers and powers off the hardware, the video devices are still registered and the worker thread can still be triggered by the hrtimer, causing it to attempt reading registers from powered-off hardware. This results in a bus error (synchronous external abort) and kernel panic. This causes random kernel panics during encoding operations: Internal error: synchronous external abort: 0000000096000010 [#1] PREEMPT SMP Modules linked in: wave5 rpmsg_ctrl rpmsg_char ... CPU: 0 UID: 0 PID: 1520 Comm: vpu_irq_thread Tainted: G M W pc : wave5_vdi_read_register+0x10/0x38 [wave5] lr : wave5_vpu_irq_work_fn+0x28/0x60 [wave5] Call trace: wave5_vdi_read_register+0x10/0x38 [wave5] kthread_worker_fn+0xd8/0x238 kthread+0x104/0x120 ret_from_fork+0x10/0x20 Code: aa1e03e9 d503201f f9416800 8b214000 (b9400000) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: synchronous external abort: Fatal exception
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: cgroup: Avoid iteration of dying tasks with zero refcount The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()") extended the lifetime of tasks on the dying_tasks list. The iterators have provision to go through dying_tasks because of dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however, it was expected that such tasks can obtain a new reference (that is possible before cgroup_task_release()/put_task_struct_rcu_user()). The tasks after cgroup_task_release() and before cgroup_task_free() are subject to race when they may or may not have ->usage count > 0. The race window is between css_task_iter_next() invocations when css_set_lock is released and we may arrive at a new ->task_pos. The iterator should not attempt to resurrect tasks whose ->usage count dropped to zero. (When that happens, __put_task_struct_rcu_cb() is already imminent and the returned task_struct would could be used after free.) As for the fix, we cannot simply check the signal->live count of a task on the dying list because that won't distinguish regular zombies waiting to be reaped from RCU remnant tasks that are going to be free'd. Therefore add an extra check to rule out ->usage==0 tasks from any iteration. The repeat: loop in css_task_iter_advance() doesn't consider ->usage count, so add a new loop to css_task_iter_next() to skip de-used tasks on the dying_list. Rough illustration of the possible race R (reader of cgroup.procs) T (thread) L (group leader) --------------------------------- -------------------------------- -------------------------------- L exits, signal->live > 0 cgroup_task_dead(L) css_set_skip_task_iters() // skips only cset->tasks list_add_tail(&L->cg_list, &cset->dying_tasks) css_task_iter_next() take css_set_lock css_task_iter_advance() leader && signal->live != 0 => it->task_pos = &L->cg_list release css_set_lock T exits --signal->live == 0 cgroup_task_dead(T) // css_set_lock release_task(T) cgroup_task_release(T) release_task(L) // zap_leader cgroup_task_release(L) put_task_struct_rcu_user(L) ...RCU... put_task_struct(L) L->usage = 0 /* L still on dying_tasks */ ...RCU... __put_task_struct(L) css_task_iter_next() // another iteration take css_set_lock it->task_pos = &L->cg_list get_task_struct(L) => addition on 0 drop css_set_lock cgroup_task_free(L) css_set_skip_task_iters() // dying skip comes too late free_task(L) cgroup_procs_show() task_pid_vnr(L)•CVE-2026-98163