CVE-2023-53029

Published Mar 27, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: octeontx2-pf: Fix the use of GFP_KERNEL in atomic context on rt The commit 4af1b64f80fb ("octeontx2-pf: Fix lmtst ID used in aura free") uses the get/put_cpu() to protect the usage of percpu pointer in ->aura_freeptr() callback, but it also unnecessarily disable the preemption for the blockable memory allocation. The commit 87b93b678e95 ("octeontx2-pf: Avoid use of GFP_KERNEL in atomic context") tried to fix these sleep inside atomic warnings. But it only fix the one for the non-rt kernel. For the rt kernel, we still get the similar warnings like below. BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 3 locks held by swapper/0/1: #0: ffff800009fc5fe8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x24/0x30 #1: ffff000100c276c0 (&mbox->lock){+.+.}-{3:3}, at: otx2_init_hw_resources+0x8c/0x3a4 #2: ffffffbfef6537e0 (&cpu_rcache->lock){+.+.}-{2:2}, at: alloc_iova_fast+0x1ac/0x2ac Preemption disabled at: [<ffff800008b1908c>] otx2_rq_aura_pool_init+0x14c/0x284 CPU: 20 PID: 1 Comm: swapper/0 Tainted: G W 6.2.0-rc3-rt1-yocto-preempt-rt #1 Hardware name: Marvell OcteonTX CN96XX board (DT) Call trace: dump_backtrace.part.0+0xe8/0xf4 show_stack+0x20/0x30 dump_stack_lvl+0x9c/0xd8 dump_stack+0x18/0x34 __might_resched+0x188/0x224 rt_spin_lock+0x64/0x110 alloc_iova_fast+0x1ac/0x2ac iommu_dma_alloc_iova+0xd4/0x110 __iommu_dma_map+0x80/0x144 iommu_dma_map_page+0xe8/0x260 dma_map_page_attrs+0xb4/0xc0 __otx2_alloc_rbuf+0x90/0x150 otx2_rq_aura_pool_init+0x1c8/0x284 otx2_init_hw_resources+0xe4/0x3a4 otx2_open+0xf0/0x610 __dev_open+0x104/0x224 __dev_change_flags+0x1e4/0x274 dev_change_flags+0x2c/0x7c ic_open_devs+0x124/0x2f8 ip_auto_config+0x180/0x42c do_one_initcall+0x90/0x4dc do_basic_setup+0x10c/0x14c kernel_init_freeable+0x10c/0x13c kernel_init+0x2c/0x140 ret_from_fork+0x10/0x20 Of course, we can shuffle the get/put_cpu() to only wrap the invocation of ->aura_freeptr() as what commit 87b93b678e95 does. But there are only two ->aura_freeptr() callbacks, otx2_aura_freeptr() and cn10k_aura_freeptr(). There is no usage of perpcu variable in the otx2_aura_freeptr() at all, so the get/put_cpu() seems redundant to it. We can move the get/put_cpu() into the corresponding callback which really has the percpu variable usage and avoid the sprinkling of get/put_cpu() in several places.
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