CVE-2022-49509

Published Feb 26, 2025

Last updated 9 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: media: i2c: max9286: fix kernel oops when removing module When removing the max9286 module we get a kernel oops: Unable to handle kernel paging request at virtual address 000000aa00000094 Mem abort info: ESR = 0x96000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 user pgtable: 4k pages, 48-bit VAs, pgdp=0000000880d85000 [000000aa00000094] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 96000004 [#1] PREEMPT SMP Modules linked in: fsl_jr_uio caam_jr rng_core libdes caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine max9271 authenc crct10dif_ce mxc_jpeg_encdec CPU: 2 PID: 713 Comm: rmmod Tainted: G C 5.15.5-00057-gaebcd29c8ed7-dirty #5 Hardware name: Freescale i.MX8QXP MEK (DT) pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : i2c_mux_del_adapters+0x24/0xf0 lr : max9286_remove+0x28/0xd0 [max9286] sp : ffff800013a9bbf0 x29: ffff800013a9bbf0 x28: ffff00080b6da940 x27: 0000000000000000 x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 x23: ffff000801a5b970 x22: ffff0008048b0890 x21: ffff800009297000 x20: ffff0008048b0f70 x19: 000000aa00000064 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000014 x13: 0000000000000000 x12: ffff000802da49e8 x11: ffff000802051918 x10: ffff000802da4920 x9 : ffff000800030098 x8 : 0101010101010101 x7 : 7f7f7f7f7f7f7f7f x6 : fefefeff6364626d x5 : 8080808000000000 x4 : 0000000000000000 x3 : 0000000000000000 x2 : ffffffffffffffff x1 : ffff00080b6da940 x0 : 0000000000000000 Call trace: i2c_mux_del_adapters+0x24/0xf0 max9286_remove+0x28/0xd0 [max9286] i2c_device_remove+0x40/0x110 __device_release_driver+0x188/0x234 driver_detach+0xc4/0x150 bus_remove_driver+0x60/0xe0 driver_unregister+0x34/0x64 i2c_del_driver+0x58/0xa0 max9286_i2c_driver_exit+0x1c/0x490 [max9286] __arm64_sys_delete_module+0x194/0x260 invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0xd4/0xfc do_el0_svc+0x2c/0x94 el0_svc+0x28/0x80 el0t_64_sync_handler+0xa8/0x130 el0t_64_sync+0x1a0/0x1a4 The Oops happens because the I2C client data does not point to max9286_priv anymore but to v4l2_subdev. The change happened in max9286_init() which calls v4l2_i2c_subdev_init() later on... Besides fixing the max9286_remove() function, remove the call to i2c_set_clientdata() in max9286_probe(), to avoid confusion, and make the necessary changes to max9286_init() so that it doesn't have to use i2c_get_clientdata() in order to fetch the pointer to priv.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
7.1
Impact score
5.2
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-668

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