CVE-2025-39907

Published Oct 1, 2025

Last updated 4 days ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: mtd: rawnand: stm32_fmc2: avoid overlapping mappings on ECC buffer Avoid below overlapping mappings by using a contiguous non-cacheable buffer. [ 4.077708] DMA-API: stm32_fmc2_nfc 48810000.nand-controller: cacheline tracking EEXIST, overlapping mappings aren't supported [ 4.089103] WARNING: CPU: 1 PID: 44 at kernel/dma/debug.c:568 add_dma_entry+0x23c/0x300 [ 4.097071] Modules linked in: [ 4.100101] CPU: 1 PID: 44 Comm: kworker/u4:2 Not tainted 6.1.82 #1 [ 4.106346] Hardware name: STMicroelectronics STM32MP257F VALID1 SNOR / MB1704 (LPDDR4 Power discrete) + MB1703 + MB1708 (SNOR MB1730) (DT) [ 4.118824] Workqueue: events_unbound deferred_probe_work_func [ 4.124674] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 4.131624] pc : add_dma_entry+0x23c/0x300 [ 4.135658] lr : add_dma_entry+0x23c/0x300 [ 4.139792] sp : ffff800009dbb490 [ 4.143016] x29: ffff800009dbb4a0 x28: 0000000004008022 x27: ffff8000098a6000 [ 4.150174] x26: 0000000000000000 x25: ffff8000099e7000 x24: ffff8000099e7de8 [ 4.157231] x23: 00000000ffffffff x22: 0000000000000000 x21: ffff8000098a6a20 [ 4.164388] x20: ffff000080964180 x19: ffff800009819ba0 x18: 0000000000000006 [ 4.171545] x17: 6361727420656e69 x16: 6c6568636163203a x15: 72656c6c6f72746e [ 4.178602] x14: 6f632d646e616e2e x13: ffff800009832f58 x12: 00000000000004ec [ 4.185759] x11: 00000000000001a4 x10: ffff80000988af58 x9 : ffff800009832f58 [ 4.192916] x8 : 00000000ffffefff x7 : ffff80000988af58 x6 : 80000000fffff000 [ 4.199972] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000 [ 4.207128] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000812d2c40 [ 4.214185] Call trace: [ 4.216605] add_dma_entry+0x23c/0x300 [ 4.220338] debug_dma_map_sg+0x198/0x350 [ 4.224373] __dma_map_sg_attrs+0xa0/0x110 [ 4.228411] dma_map_sg_attrs+0x10/0x2c [ 4.232247] stm32_fmc2_nfc_xfer.isra.0+0x1c8/0x3fc [ 4.237088] stm32_fmc2_nfc_seq_read_page+0xc8/0x174 [ 4.242127] nand_read_oob+0x1d4/0x8e0 [ 4.245861] mtd_read_oob_std+0x58/0x84 [ 4.249596] mtd_read_oob+0x90/0x150 [ 4.253231] mtd_read+0x68/0xac
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel, debian_linux

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