CVE-2022-49536

Published Feb 26, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Fix SCSI I/O completion and abort handler deadlock During stress I/O tests with 500+ vports, hard LOCKUP call traces are observed. CPU A: native_queued_spin_lock_slowpath+0x192 _raw_spin_lock_irqsave+0x32 lpfc_handle_fcp_err+0x4c6 lpfc_fcp_io_cmd_wqe_cmpl+0x964 lpfc_sli4_fp_handle_cqe+0x266 __lpfc_sli4_process_cq+0x105 __lpfc_sli4_hba_process_cq+0x3c lpfc_cq_poll_hdler+0x16 irq_poll_softirq+0x76 __softirqentry_text_start+0xe4 irq_exit+0xf7 do_IRQ+0x7f CPU B: native_queued_spin_lock_slowpath+0x5b _raw_spin_lock+0x1c lpfc_abort_handler+0x13e scmd_eh_abort_handler+0x85 process_one_work+0x1a7 worker_thread+0x30 kthread+0x112 ret_from_fork+0x1f Diagram of lockup: CPUA CPUB ---- ---- lpfc_cmd->buf_lock phba->hbalock lpfc_cmd->buf_lock phba->hbalock Fix by reordering the taking of the lpfc_cmd->buf_lock and phba->hbalock in lpfc_abort_handler routine so that it tries to take the lpfc_cmd->buf_lock first before phba->hbalock.
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
CWE-667
134c704f-9b21-4f2e-91b3-4a467353bcc0
CWE-667

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