CVE-2022-50270

Published Sep 15, 2025

Last updated 3 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix the assign logic of iocb commit 18ae8d12991b ("f2fs: show more DIO information in tracepoint") introduces iocb field in 'f2fs_direct_IO_enter' trace event And it only assigns the pointer and later it accesses its field in trace print log. Unable to handle kernel paging request at virtual address ffffffc04cef3d30 Mem abort info: ESR = 0x96000007 EC = 0x25: DABT (current EL), IL = 32 bits pc : trace_raw_output_f2fs_direct_IO_enter+0x54/0xa4 lr : trace_raw_output_f2fs_direct_IO_enter+0x2c/0xa4 sp : ffffffc0443cbbd0 x29: ffffffc0443cbbf0 x28: ffffff8935b120d0 x27: ffffff8935b12108 x26: ffffff8935b120f0 x25: ffffff8935b12100 x24: ffffff8935b110c0 x23: ffffff8935b10000 x22: ffffff88859a936c x21: ffffff88859a936c x20: ffffff8935b110c0 x19: ffffff8935b10000 x18: ffffffc03b195060 x17: ffffff8935b11e76 x16: 00000000000000cc x15: ffffffef855c4f2c x14: 0000000000000001 x13: 000000000000004e x12: ffff0000ffffff00 x11: ffffffef86c350d0 x10: 00000000000010c0 x9 : 000000000fe0002c x8 : ffffffc04cef3d28 x7 : 7f7f7f7f7f7f7f7f x6 : 0000000002000000 x5 : ffffff8935b11e9a x4 : 0000000000006250 x3 : ffff0a00ffffff04 x2 : 0000000000000002 x1 : ffffffef86a0a31f x0 : ffffff8935b10000 Call trace: trace_raw_output_f2fs_direct_IO_enter+0x54/0xa4 print_trace_fmt+0x9c/0x138 print_trace_line+0x154/0x254 tracing_read_pipe+0x21c/0x380 vfs_read+0x108/0x3ac ksys_read+0x7c/0xec __arm64_sys_read+0x20/0x30 invoke_syscall+0x60/0x150 el0_svc_common.llvm.1237943816091755067+0xb8/0xf8 do_el0_svc+0x28/0xa0 Fix it by copying the required variables for printing and while at it fix the similar issue at some other places in the same file.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
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
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