CVE-2022-50211

Published Jun 18, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: md-raid10: fix KASAN warning There's a KASAN warning in raid10_remove_disk when running the lvm test lvconvert-raid-reshape.sh. We fix this warning by verifying that the value "number" is valid. BUG: KASAN: slab-out-of-bounds in raid10_remove_disk+0x61/0x2a0 [raid10] Read of size 8 at addr ffff889108f3d300 by task mdX_raid10/124682 CPU: 3 PID: 124682 Comm: mdX_raid10 Not tainted 5.19.0-rc6 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x34/0x44 print_report.cold+0x45/0x57a ? __lock_text_start+0x18/0x18 ? raid10_remove_disk+0x61/0x2a0 [raid10] kasan_report+0xa8/0xe0 ? raid10_remove_disk+0x61/0x2a0 [raid10] raid10_remove_disk+0x61/0x2a0 [raid10] Buffer I/O error on dev dm-76, logical block 15344, async page read ? __mutex_unlock_slowpath.constprop.0+0x1e0/0x1e0 remove_and_add_spares+0x367/0x8a0 [md_mod] ? super_written+0x1c0/0x1c0 [md_mod] ? mutex_trylock+0xac/0x120 ? _raw_spin_lock+0x72/0xc0 ? _raw_spin_lock_bh+0xc0/0xc0 md_check_recovery+0x848/0x960 [md_mod] raid10d+0xcf/0x3360 [raid10] ? sched_clock_cpu+0x185/0x1a0 ? rb_erase+0x4d4/0x620 ? var_wake_function+0xe0/0xe0 ? psi_group_change+0x411/0x500 ? preempt_count_sub+0xf/0xc0 ? _raw_spin_lock_irqsave+0x78/0xc0 ? __lock_text_start+0x18/0x18 ? raid10_sync_request+0x36c0/0x36c0 [raid10] ? preempt_count_sub+0xf/0xc0 ? _raw_spin_unlock_irqrestore+0x19/0x40 ? del_timer_sync+0xa9/0x100 ? try_to_del_timer_sync+0xc0/0xc0 ? _raw_spin_lock_irqsave+0x78/0xc0 ? __lock_text_start+0x18/0x18 ? _raw_spin_unlock_irq+0x11/0x24 ? __list_del_entry_valid+0x68/0xa0 ? finish_wait+0xa3/0x100 md_thread+0x161/0x260 [md_mod] ? unregister_md_personality+0xa0/0xa0 [md_mod] ? _raw_spin_lock_irqsave+0x78/0xc0 ? prepare_to_wait_event+0x2c0/0x2c0 ? unregister_md_personality+0xa0/0xa0 [md_mod] kthread+0x148/0x180 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 </TASK> Allocated by task 124495: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0x80/0xa0 setup_conf+0x140/0x5c0 [raid10] raid10_run+0x4cd/0x740 [raid10] md_run+0x6f9/0x1300 [md_mod] raid_ctr+0x2531/0x4ac0 [dm_raid] dm_table_add_target+0x2b0/0x620 [dm_mod] table_load+0x1c8/0x400 [dm_mod] ctl_ioctl+0x29e/0x560 [dm_mod] dm_compat_ctl_ioctl+0x7/0x20 [dm_mod] __do_compat_sys_ioctl+0xfa/0x160 do_syscall_64+0x90/0xc0 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Last potentially related work creation: kasan_save_stack+0x1e/0x40 __kasan_record_aux_stack+0x9e/0xc0 kvfree_call_rcu+0x84/0x480 timerfd_release+0x82/0x140 L __fput+0xfa/0x400 task_work_run+0x80/0xc0 exit_to_user_mode_prepare+0x155/0x160 syscall_exit_to_user_mode+0x12/0x40 do_syscall_64+0x42/0xc0 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Second to last potentially related work creation: kasan_save_stack+0x1e/0x40 __kasan_record_aux_stack+0x9e/0xc0 kvfree_call_rcu+0x84/0x480 timerfd_release+0x82/0x140 __fput+0xfa/0x400 task_work_run+0x80/0xc0 exit_to_user_mode_prepare+0x155/0x160 syscall_exit_to_user_mode+0x12/0x40 do_syscall_64+0x42/0xc0 entry_SYSCALL_64_after_hwframe+0x46/0xb0 The buggy address belongs to the object at ffff889108f3d200 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 0 bytes to the right of 256-byte region [ffff889108f3d200, ffff889108f3d300) The buggy address belongs to the physical page: page:000000007ef2a34c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1108f3c head:000000007ef2a34c order:2 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=2) raw: 4000000000010200 0000000000000000 dead000000000001 ffff889100042b40 raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff889108f3d200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff889108f3d280: 00 00 ---truncated---
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
7.1
Impact score
5.2
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-125

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