CVE-2022-49701

Published Feb 26, 2025

Last updated 3 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: scsi: ibmvfc: Allocate/free queue resource only during probe/remove Currently, the sub-queues and event pool resources are allocated/freed for every CRQ connection event such as reset and LPM. This exposes the driver to a couple issues. First the inefficiency of freeing and reallocating memory that can simply be resued after being sanitized. Further, a system under memory pressue runs the risk of allocation failures that could result in a crippled driver. Finally, there is a race window where command submission/compeletion can try to pull/return elements from/to an event pool that is being deleted or already has been deleted due to the lack of host state around freeing/allocating resources. The following is an example of list corruption following a live partition migration (LPM): Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: vfat fat isofs cdrom ext4 mbcache jbd2 nft_counter nft_compat nf_tables nfnetlink rpadlpar_io rpaphp xsk_diag nfsv3 nfs_acl nfs lockd grace fscache netfs rfkill bonding tls sunrpc pseries_rng drm drm_panel_orientation_quirks xfs libcrc32c dm_service_time sd_mod t10_pi sg ibmvfc scsi_transport_fc ibmveth vmx_crypto dm_multipath dm_mirror dm_region_hash dm_log dm_mod ipmi_devintf ipmi_msghandler fuse CPU: 0 PID: 2108 Comm: ibmvfc_0 Kdump: loaded Not tainted 5.14.0-70.9.1.el9_0.ppc64le #1 NIP: c0000000007c4bb0 LR: c0000000007c4bac CTR: 00000000005b9a10 REGS: c00000025c10b760 TRAP: 0700 Not tainted (5.14.0-70.9.1.el9_0.ppc64le) MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 2800028f XER: 0000000f CFAR: c0000000001f55bc IRQMASK: 0 GPR00: c0000000007c4bac c00000025c10ba00 c000000002a47c00 000000000000004e GPR04: c0000031e3006f88 c0000031e308bd00 c00000025c10b768 0000000000000027 GPR08: 0000000000000000 c0000031e3009dc0 00000031e0eb0000 0000000000000000 GPR12: c0000031e2ffffa8 c000000002dd0000 c000000000187108 c00000020fcee2c0 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 c008000002f81300 GPR24: 5deadbeef0000100 5deadbeef0000122 c000000263ba6910 c00000024cc88000 GPR28: 000000000000003c c0000002430a0000 c0000002430ac300 000000000000c300 NIP [c0000000007c4bb0] __list_del_entry_valid+0x90/0x100 LR [c0000000007c4bac] __list_del_entry_valid+0x8c/0x100 Call Trace: [c00000025c10ba00] [c0000000007c4bac] __list_del_entry_valid+0x8c/0x100 (unreliable) [c00000025c10ba60] [c008000002f42284] ibmvfc_free_queue+0xec/0x210 [ibmvfc] [c00000025c10bb10] [c008000002f4246c] ibmvfc_deregister_scsi_channel+0xc4/0x160 [ibmvfc] [c00000025c10bba0] [c008000002f42580] ibmvfc_release_sub_crqs+0x78/0x130 [ibmvfc] [c00000025c10bc20] [c008000002f4f6cc] ibmvfc_do_work+0x5c4/0xc70 [ibmvfc] [c00000025c10bce0] [c008000002f4fdec] ibmvfc_work+0x74/0x1e8 [ibmvfc] [c00000025c10bda0] [c0000000001872b8] kthread+0x1b8/0x1c0 [c00000025c10be10] [c00000000000cd64] ret_from_kernel_thread+0x5c/0x64 Instruction dump: 40820034 38600001 38210060 4e800020 7c0802a6 7c641b78 3c62fe7a 7d254b78 3863b590 f8010070 4ba309cd 60000000 <0fe00000> 7c0802a6 3c62fe7a 3863b640 ---[ end trace 11a2b65a92f8b66c ]--- ibmvfc 30000003: Send warning. Receive queue closed, will retry. Add registration/deregistration helpers that are called instead during connection resets to sanitize and reconfigure the queues.
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-401

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