CVE-2022-49584

Published Feb 26, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: ixgbe: Add locking to prevent panic when setting sriov_numvfs to zero It is possible to disable VFs while the PF driver is processing requests from the VF driver. This can result in a panic. BUG: unable to handle kernel paging request at 000000000000106c PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 8 PID: 0 Comm: swapper/8 Kdump: loaded Tainted: G I --------- - Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020 RIP: 0010:ixgbe_msg_task+0x4c8/0x1690 [ixgbe] Code: 00 00 48 8d 04 40 48 c1 e0 05 89 7c 24 24 89 fd 48 89 44 24 10 83 ff 01 0f 84 b8 04 00 00 4c 8b 64 24 10 4d 03 a5 48 22 00 00 <41> 80 7c 24 4c 00 0f 84 8a 03 00 00 0f b7 c7 83 f8 08 0f 84 8f 0a RSP: 0018:ffffb337869f8df8 EFLAGS: 00010002 RAX: 0000000000001020 RBX: 0000000000000000 RCX: 000000000000002b RDX: 0000000000000002 RSI: 0000000000000008 RDI: 0000000000000006 RBP: 0000000000000006 R08: 0000000000000002 R09: 0000000000029780 R10: 00006957d8f42832 R11: 0000000000000000 R12: 0000000000001020 R13: ffff8a00e8978ac0 R14: 000000000000002b R15: ffff8a00e8979c80 FS: 0000000000000000(0000) GS:ffff8a07dfd00000(0000) knlGS:00000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000106c CR3: 0000000063e10004 CR4: 00000000007726e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> ? ttwu_do_wakeup+0x19/0x140 ? try_to_wake_up+0x1cd/0x550 ? ixgbevf_update_xcast_mode+0x71/0xc0 [ixgbevf] ixgbe_msix_other+0x17e/0x310 [ixgbe] __handle_irq_event_percpu+0x40/0x180 handle_irq_event_percpu+0x30/0x80 handle_irq_event+0x36/0x53 handle_edge_irq+0x82/0x190 handle_irq+0x1c/0x30 do_IRQ+0x49/0xd0 common_interrupt+0xf/0xf This can be eventually be reproduced with the following script: while : do echo 63 > /sys/class/net/<devname>/device/sriov_numvfs sleep 1 echo 0 > /sys/class/net/<devname>/device/sriov_numvfs sleep 1 done Add lock when disabling SR-IOV to prevent process VF mailbox communication.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
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

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