CVE-2022-50362

Published Sep 17, 2025

Last updated 3 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: dmaengine: hisilicon: Add multi-thread support for a DMA channel When we get a DMA channel and try to use it in multiple threads it will cause oops and hanging the system. % echo 100 > /sys/module/dmatest/parameters/threads_per_chan % echo 100 > /sys/module/dmatest/parameters/iterations % echo 1 > /sys/module/dmatest/parameters/run [383493.327077] Unable to handle kernel paging request at virtual address dead000000000108 [383493.335103] Mem abort info: [383493.335103] ESR = 0x96000044 [383493.335105] EC = 0x25: DABT (current EL), IL = 32 bits [383493.335107] SET = 0, FnV = 0 [383493.335108] EA = 0, S1PTW = 0 [383493.335109] FSC = 0x04: level 0 translation fault [383493.335110] Data abort info: [383493.335111] ISV = 0, ISS = 0x00000044 [383493.364739] CM = 0, WnR = 1 [383493.367793] [dead000000000108] address between user and kernel address ranges [383493.375021] Internal error: Oops: 96000044 [#1] PREEMPT SMP [383493.437574] CPU: 63 PID: 27895 Comm: dma0chan0-copy2 Kdump: loaded Tainted: GO 5.17.0-rc4+ #2 [383493.457851] pstate: 204000c9 (nzCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [383493.465331] pc : vchan_tx_submit+0x64/0xa0 [383493.469957] lr : vchan_tx_submit+0x34/0xa0 This occurs because the transmission timed out, and that's due to data race. Each thread rewrite channels's descriptor as soon as device_issue_pending is called. It leads to the situation that the driver thinks that it uses the right descriptor in interrupt handler while channels's descriptor has been changed by other thread. The descriptor which in fact reported interrupt will not be handled any more, as well as its tx->callback. That's why timeout reports. With current fixes channels' descriptor changes it's value only when it has been used. A new descriptor is acquired from vc->desc_issued queue that is already filled with descriptors that are ready to be sent. Threads have no direct access to DMA channel descriptor. In case of channel's descriptor is busy, try to submit to HW again when a descriptor is completed. In this case, vc->desc_issued may be empty when hisi_dma_start_transfer is called, so delete error reporting on this. Now it is just possible to queue a descriptor for further processing.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
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