CVE-2022-49519

Published Feb 26, 2025

Last updated 2 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: ath10k: skip ath10k_halt during suspend for driver state RESTARTING Double free crash is observed when FW recovery(caused by wmi timeout/crash) is followed by immediate suspend event. The FW recovery is triggered by ath10k_core_restart() which calls driver clean up via ath10k_halt(). When the suspend event occurs between the FW recovery, the restart worker thread is put into frozen state until suspend completes. The suspend event triggers ath10k_stop() which again triggers ath10k_halt() The double invocation of ath10k_halt() causes ath10k_htt_rx_free() to be called twice(Note: ath10k_htt_rx_alloc was not called by restart worker thread because of its frozen state), causing the crash. To fix this, during the suspend flow, skip call to ath10k_halt() in ath10k_stop() when the current driver state is ATH10K_STATE_RESTARTING. Also, for driver state ATH10K_STATE_RESTARTING, call ath10k_wait_for_suspend() in ath10k_stop(). This is because call to ath10k_wait_for_suspend() is skipped later in [ath10k_halt() > ath10k_core_stop()] for the driver state ATH10K_STATE_RESTARTING. The frozen restart worker thread will be cancelled during resume when the device comes out of suspend. Below is the crash stack for reference: [ 428.469167] ------------[ cut here ]------------ [ 428.469180] kernel BUG at mm/slub.c:4150! [ 428.469193] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI [ 428.469219] Workqueue: events_unbound async_run_entry_fn [ 428.469230] RIP: 0010:kfree+0x319/0x31b [ 428.469241] RSP: 0018:ffffa1fac015fc30 EFLAGS: 00010246 [ 428.469247] RAX: ffffedb10419d108 RBX: ffff8c05262b0000 [ 428.469252] RDX: ffff8c04a8c07000 RSI: 0000000000000000 [ 428.469256] RBP: ffffa1fac015fc78 R08: 0000000000000000 [ 428.469276] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 428.469285] Call Trace: [ 428.469295] ? dma_free_attrs+0x5f/0x7d [ 428.469320] ath10k_core_stop+0x5b/0x6f [ 428.469336] ath10k_halt+0x126/0x177 [ 428.469352] ath10k_stop+0x41/0x7e [ 428.469387] drv_stop+0x88/0x10e [ 428.469410] __ieee80211_suspend+0x297/0x411 [ 428.469441] rdev_suspend+0x6e/0xd0 [ 428.469462] wiphy_suspend+0xb1/0x105 [ 428.469483] ? name_show+0x2d/0x2d [ 428.469490] dpm_run_callback+0x8c/0x126 [ 428.469511] ? name_show+0x2d/0x2d [ 428.469517] __device_suspend+0x2e7/0x41b [ 428.469523] async_suspend+0x1f/0x93 [ 428.469529] async_run_entry_fn+0x3d/0xd1 [ 428.469535] process_one_work+0x1b1/0x329 [ 428.469541] worker_thread+0x213/0x372 [ 428.469547] kthread+0x150/0x15f [ 428.469552] ? pr_cont_work+0x58/0x58 [ 428.469558] ? kthread_blkcg+0x31/0x31 Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00288-QCARMSWPZ-1
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-415

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