CVE-2023-53347

Published Sep 17, 2025

Last updated 9 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Handle pairing of E-switch via uplink un/load APIs In case user switch a device from switchdev mode to legacy mode, mlx5 first unpair the E-switch and afterwards unload the uplink vport. From the other hand, in case user remove or reload a device, mlx5 first unload the uplink vport and afterwards unpair the E-switch. The latter is causing a bug[1], hence, handle pairing of E-switch as part of uplink un/load APIs. [1] In case VF_LAG is used, every tc fdb flow is duplicated to the peer esw. However, the original esw keeps a pointer to this duplicated flow, not the peer esw. e.g.: if user create tc fdb flow over esw0, the flow is duplicated over esw1, in FW/HW, but in SW, esw0 keeps a pointer to the duplicated flow. During module unload while a peer tc fdb flow is still offloaded, in case the first device to be removed is the peer device (esw1 in the example above), the peer net-dev is destroyed, and so the mlx5e_priv is memset to 0. Afterwards, the peer device is trying to unpair himself from the original device (esw0 in the example above). Unpair API invoke the original device to clear peer flow from its eswitch (esw0), but the peer flow, which is stored over the original eswitch (esw0), is trying to use the peer mlx5e_priv, which is memset to 0 and result in bellow kernel-oops. [ 157.964081 ] BUG: unable to handle page fault for address: 000000000002ce60 [ 157.964662 ] #PF: supervisor read access in kernel mode [ 157.965123 ] #PF: error_code(0x0000) - not-present page [ 157.965582 ] PGD 0 P4D 0 [ 157.965866 ] Oops: 0000 [#1] SMP [ 157.967670 ] RIP: 0010:mlx5e_tc_del_fdb_flow+0x48/0x460 [mlx5_core] [ 157.976164 ] Call Trace: [ 157.976437 ] <TASK> [ 157.976690 ] __mlx5e_tc_del_fdb_peer_flow+0xe6/0x100 [mlx5_core] [ 157.977230 ] mlx5e_tc_clean_fdb_peer_flows+0x67/0x90 [mlx5_core] [ 157.977767 ] mlx5_esw_offloads_unpair+0x2d/0x1e0 [mlx5_core] [ 157.984653 ] mlx5_esw_offloads_devcom_event+0xbf/0x130 [mlx5_core] [ 157.985212 ] mlx5_devcom_send_event+0xa3/0xb0 [mlx5_core] [ 157.985714 ] esw_offloads_disable+0x5a/0x110 [mlx5_core] [ 157.986209 ] mlx5_eswitch_disable_locked+0x152/0x170 [mlx5_core] [ 157.986757 ] mlx5_eswitch_disable+0x51/0x80 [mlx5_core] [ 157.987248 ] mlx5_unload+0x2a/0xb0 [mlx5_core] [ 157.987678 ] mlx5_uninit_one+0x5f/0xd0 [mlx5_core] [ 157.988127 ] remove_one+0x64/0xe0 [mlx5_core] [ 157.988549 ] pci_device_remove+0x31/0xa0 [ 157.988933 ] device_release_driver_internal+0x18f/0x1f0 [ 157.989402 ] driver_detach+0x3f/0x80 [ 157.989754 ] bus_remove_driver+0x70/0xf0 [ 157.990129 ] pci_unregister_driver+0x34/0x90 [ 157.990537 ] mlx5_cleanup+0xc/0x1c [mlx5_core] [ 157.990972 ] __x64_sys_delete_module+0x15a/0x250 [ 157.991398 ] ? exit_to_user_mode_prepare+0xea/0x110 [ 157.991840 ] do_syscall_64+0x3d/0x90 [ 157.992198 ] entry_SYSCALL_64_after_hwframe+0x46/0xb0
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