CVE-2026-23000

Published Jan 25, 2026

Last updated 8 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix crash on profile change rollback failure mlx5e_netdev_change_profile can fail to attach a new profile and can fail to rollback to old profile, in such case, we could end up with a dangling netdev with a fully reset netdev_priv. A retry to change profile, e.g. another attempt to call mlx5e_netdev_change_profile via switchdev mode change, will crash trying to access the now NULL priv->mdev. This fix allows mlx5e_netdev_change_profile() to handle previous failures and an empty priv, by not assuming priv is valid. Pass netdev and mdev to all flows requiring mlx5e_netdev_change_profile() and avoid passing priv. In mlx5e_netdev_change_profile() check if current priv is valid, and if not, just attach the new profile without trying to access the old one. This fixes the following oops, when enabling switchdev mode for the 2nd time after first time failure: ## Enabling switchdev mode first time: mlx5_core 0012:03:00.1: E-Switch: Supported tc chains and prios offload workqueue: Failed to create a rescuer kthread for wq "mlx5e": -EINTR mlx5_core 0012:03:00.1: mlx5e_netdev_init_profile:6214:(pid 37199): mlx5e_priv_init failed, err=-12 mlx5_core 0012:03:00.1 gpu3rdma1: mlx5e_netdev_change_profile: new profile init failed, -12 workqueue: Failed to create a rescuer kthread for wq "mlx5e": -EINTR mlx5_core 0012:03:00.1: mlx5e_netdev_init_profile:6214:(pid 37199): mlx5e_priv_init failed, err=-12 mlx5_core 0012:03:00.1 gpu3rdma1: mlx5e_netdev_change_profile: failed to rollback to orig profile, -12 ^^^^^^^^ mlx5_core 0000:00:03.0: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0) ## retry: Enabling switchdev mode 2nd time: mlx5_core 0000:00:03.0: E-Switch: Supported tc chains and prios offload BUG: kernel NULL pointer dereference, address: 0000000000000038 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 13 UID: 0 PID: 520 Comm: devlink Not tainted 6.18.0-rc4+ #91 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014 RIP: 0010:mlx5e_detach_netdev+0x3c/0x90 Code: 50 00 00 f0 80 4f 78 02 48 8b bf e8 07 00 00 48 85 ff 74 16 48 8b 73 78 48 d1 ee 83 e6 01 83 f6 01 40 0f b6 f6 e8 c4 42 00 00 <48> 8b 45 38 48 85 c0 74 08 48 89 df e8 cc 47 40 1e 48 8b bb f0 07 RSP: 0018:ffffc90000673890 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8881036a89c0 RCX: 0000000000000000 RDX: ffff888113f63800 RSI: ffffffff822fe720 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000002dcd R09: 0000000000000000 R10: ffffc900006738e8 R11: 00000000ffffffff R12: 0000000000000000 R13: 0000000000000000 R14: ffff8881036a89c0 R15: 0000000000000000 FS: 00007fdfb8384740(0000) GS:ffff88856a9d6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000038 CR3: 0000000112ae0005 CR4: 0000000000370ef0 Call Trace: <TASK> mlx5e_netdev_change_profile+0x45/0xb0 mlx5e_vport_rep_load+0x27b/0x2d0 mlx5_esw_offloads_rep_load+0x72/0xf0 esw_offloads_enable+0x5d0/0x970 mlx5_eswitch_enable_locked+0x349/0x430 ? is_mp_supported+0x57/0xb0 mlx5_devlink_eswitch_mode_set+0x26b/0x430 devlink_nl_eswitch_set_doit+0x6f/0xf0 genl_family_rcv_msg_doit+0xe8/0x140 genl_rcv_msg+0x18b/0x290 ? __pfx_devlink_nl_pre_doit+0x10/0x10 ? __pfx_devlink_nl_eswitch_set_doit+0x10/0x10 ? __pfx_devlink_nl_post_doit+0x10/0x10 ? __pfx_genl_rcv_msg+0x10/0x10 netlink_rcv_skb+0x52/0x100 genl_rcv+0x28/0x40 netlink_unicast+0x282/0x3e0 ? __alloc_skb+0xd6/0x190 netlink_sendmsg+0x1f7/0x430 __sys_sendto+0x213/0x220 ? __sys_recvmsg+0x6a/0xd0 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x50/0x1f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fdfb8495047
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-476

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