CVE-2026-43302

Published May 8, 2026

Last updated 5 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: drm/v3d: Set DMA segment size to avoid debug warnings When using V3D rendering with CONFIG_DMA_API_DEBUG enabled, the kernel occasionally reports a segment size mismatch. This is because 'max_seg_size' is not set. The kernel defaults to 64K. setting 'max_seg_size' to the maximum will prevent 'debug_dma_map_sg()' from complaining about the over-mapping of the V3D segment length. DMA-API: v3d 1002000000.v3d: mapping sg segment longer than device claims to support [len=8290304] [max=65536] WARNING: CPU: 0 PID: 493 at kernel/dma/debug.c:1179 debug_dma_map_sg+0x330/0x388 CPU: 0 UID: 0 PID: 493 Comm: Xorg Not tainted 6.12.53-yocto-standard #1 Hardware name: Raspberry Pi 5 Model B Rev 1.0 (DT) pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : debug_dma_map_sg+0x330/0x388 lr : debug_dma_map_sg+0x330/0x388 sp : ffff8000829a3ac0 x29: ffff8000829a3ac0 x28: 0000000000000001 x27: ffff8000813fe000 x26: ffffc1ffc0000000 x25: ffff00010fdeb760 x24: 0000000000000000 x23: ffff8000816a9bf0 x22: 0000000000000001 x21: 0000000000000002 x20: 0000000000000002 x19: ffff00010185e810 x18: ffffffffffffffff x17: 69766564206e6168 x16: 74207265676e6f6c x15: 20746e656d676573 x14: 20677320676e6970 x13: 5d34303334393134 x12: 0000000000000000 x11: 00000000000000c0 x10: 00000000000009c0 x9 : ffff8000800e0b7c x8 : ffff00010a315ca0 x7 : ffff8000816a5110 x6 : 0000000000000001 x5 : 000000000000002b x4 : 0000000000000002 x3 : 0000000000000008 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff00010a315280 Call trace: debug_dma_map_sg+0x330/0x388 __dma_map_sg_attrs+0xc0/0x278 dma_map_sgtable+0x30/0x58 drm_gem_shmem_get_pages_sgt+0xb4/0x140 v3d_bo_create_finish+0x28/0x130 [v3d] v3d_create_bo_ioctl+0x54/0x180 [v3d] drm_ioctl_kernel+0xc8/0x140 drm_ioctl+0x2d4/0x4d8
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
CWE-131

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