CVE-2022-50319

Published Sep 15, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: coresight: trbe: remove cpuhp instance node before remove cpuhp state cpuhp_state_add_instance() and cpuhp_state_remove_instance() should be used in pairs. Or there will lead to the warn on cpuhp_remove_multi_state() since the cpuhp_step list is not empty. The following is the error log with 'rmmod coresight-trbe': Error: Removing state 215 which has instances left. Call trace: __cpuhp_remove_state_cpuslocked+0x144/0x160 __cpuhp_remove_state+0xac/0x100 arm_trbe_device_remove+0x2c/0x60 [coresight_trbe] platform_remove+0x34/0x70 device_remove+0x54/0x90 device_release_driver_internal+0x1e4/0x250 driver_detach+0x5c/0xb0 bus_remove_driver+0x64/0xc0 driver_unregister+0x3c/0x70 platform_driver_unregister+0x20/0x30 arm_trbe_exit+0x1c/0x658 [coresight_trbe] __arm64_sys_delete_module+0x1ac/0x24c invoke_syscall+0x50/0x120 el0_svc_common.constprop.0+0x58/0x1a0 do_el0_svc+0x38/0xd0 el0_svc+0x2c/0xc0 el0t_64_sync_handler+0x1ac/0x1b0 el0t_64_sync+0x19c/0x1a0 ---[ end trace 0000000000000000 ]---
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