CVE-2022-50472

Published Oct 4, 2025

Last updated 8 days ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: IB/mad: Don't call to function that might sleep while in atomic context Tracepoints are not allowed to sleep, as such the following splat is generated due to call to ib_query_pkey() in atomic context. WARNING: CPU: 0 PID: 1888000 at kernel/trace/ring_buffer.c:2492 rb_commit+0xc1/0x220 CPU: 0 PID: 1888000 Comm: kworker/u9:0 Kdump: loaded Tainted: G OE --------- - - 4.18.0-305.3.1.el8.x86_64 #1 Hardware name: Red Hat KVM, BIOS 1.13.0-2.module_el8.3.0+555+a55c8938 04/01/2014 Workqueue: ib-comp-unb-wq ib_cq_poll_work [ib_core] RIP: 0010:rb_commit+0xc1/0x220 RSP: 0000:ffffa8ac80f9bca0 EFLAGS: 00010202 RAX: ffff8951c7c01300 RBX: ffff8951c7c14a00 RCX: 0000000000000246 RDX: ffff8951c707c000 RSI: ffff8951c707c57c RDI: ffff8951c7c14a00 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8951c7c01300 R11: 0000000000000001 R12: 0000000000000246 R13: 0000000000000000 R14: ffffffff964c70c0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8951fbc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f20e8f39010 CR3: 000000002ca10005 CR4: 0000000000170ef0 Call Trace: ring_buffer_unlock_commit+0x1d/0xa0 trace_buffer_unlock_commit_regs+0x3b/0x1b0 trace_event_buffer_commit+0x67/0x1d0 trace_event_raw_event_ib_mad_recv_done_handler+0x11c/0x160 [ib_core] ib_mad_recv_done+0x48b/0xc10 [ib_core] ? trace_event_raw_event_cq_poll+0x6f/0xb0 [ib_core] __ib_process_cq+0x91/0x1c0 [ib_core] ib_cq_poll_work+0x26/0x80 [ib_core] process_one_work+0x1a7/0x360 ? create_worker+0x1a0/0x1a0 worker_thread+0x30/0x390 ? create_worker+0x1a0/0x1a0 kthread+0x116/0x130 ? kthread_flush_work_fn+0x10/0x10 ret_from_fork+0x35/0x40 ---[ end trace 78ba8509d3830a16 ]---
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