CVE-2022-49412: In the Linux kernel, the following vulnerability has been resolved: bfq: Avoid merging queues with different parents It can happen that the parent o...

Description

In the Linux kernel, the following vulnerability has been resolved: bfq: Avoid merging queues with different parents It can happen that the parent of a bfqq changes between the moment we decide two queues are worth to merge (and set bic->stable_merge_bfqq) and the moment bfq_setup_merge() is called. This can happen e.g. because the process submitted IO for a different cgroup and thus bfqq got reparented. It can even happen that the bfqq we are merging with has parent cgroup that is already offline and going to be destroyed in which case the merge can lead to use-after-free issues such as: BUG: KASAN: use-after-free in __bfq_deactivate_entity+0x9cb/0xa50 Read of size 8 at addr ffff88800693c0c0 by task runc:[2:INIT]/10544 CPU: 0 PID: 10544 Comm: runc:[2:INIT] Tainted: G E 5.15.2-0.g5fb85fd-default #1 openSUSE Tumbleweed (unreleased) f1f3b891c72369aebecd2e43e4641a6358867c70 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0x46/0x5a print_address_description.constprop.0+0x1f/0x140 ? __bfq_deactivate_entity+0x9cb/0xa50 kasan_report.cold+0x7f/0x11b ? __bfq_deactivate_entity+0x9cb/0xa50 __bfq_deactivate_entity+0x9cb/0xa50 ? update_curr+0x32f/0x5d0 bfq_deactivate_entity+0xa0/0x1d0 bfq_del_bfqq_busy+0x28a/0x420 ? resched_curr+0x116/0x1d0 ? bfq_requeue_bfqq+0x70/0x70 ? check_preempt_wakeup+0x52b/0xbc0 __bfq_bfqq_expire+0x1a2/0x270 bfq_bfqq_expire+0xd16/0x2160 ? try_to_wake_up+0x4ee/0x1260 ? bfq_end_wr_async_queues+0xe0/0xe0 ? _raw_write_unlock_bh+0x60/0x60 ? _raw_spin_lock_irq+0x81/0xe0 bfq_idle_slice_timer+0x109/0x280 ? bfq_dispatch_request+0x4870/0x4870 __hrtimer_run_queues+0x37d/0x700 ? enqueue_hrtimer+0x1b0/0x1b0 ? kvm_clock_get_cycles+0xd/0x10 ? ktime_get_update_offsets_now+0x6f/0x280 hrtimer_interrupt+0x2c8/0x740 Fix the problem by checking that the parent of the two bfqqs we are merging in bfq_setup_merge() is the same.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.27%

17.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-416

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	< 5.4.198
Linux	Linux Kernel	>= 5.5, < 5.10.121
Linux	Linux Kernel	>= 5.13, < 5.15.46
Linux	Linux Kernel	>= 5.16, < 5.17.14
Linux	Linux Kernel	>= 5.18, < 5.18.3

References

Timeline

Published: Feb 26, 2025
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-49412?

In the Linux kernel, the following vulnerability has been resolved: bfq: Avoid merging queues with different parents It can happen that the parent of a bfqq changes between the moment we decide two queues are worth to merge (and set bic->stable_merge_bfqq) and the moment bfq_setup_merge() is called. This can happen e.g. because the process submitted IO for a different cgroup and thus bfqq got reparented. It can even happen that the bfqq we are merging with has parent cgroup that is already offline and going to be destroyed in which case the merge can lead to use-after-free issues such as: BUG: KASAN: use-after-free in __bfq_deactivate_entity+0x9cb/0xa50 Read of size 8 at addr ffff88800693c0c0 by task runc:[2:INIT]/10544 CPU: 0 PID: 10544 Comm: runc:[2:INIT] Tainted: G E 5.15.2-0.g5fb85fd-default #1 openSUSE Tumbleweed (unreleased) f1f3b891c72369aebecd2e43e4641a6358867c70 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0x46/0x5a print_address_description.constprop.0+0x1f/0x140 ? __bfq_deactivate_entity+0x9cb/0xa50 kasan_report.cold+0x7f/0x11b ? __bfq_deactivate_entity+0x9cb/0xa50 __bfq_deactivate_entity+0x9cb/0xa50 ? update_curr+0x32f/0x5d0 bfq_deactivate_entity+0xa0/0x1d0 bfq_del_bfqq_busy+0x28a/0x420 ? resched_curr+0x116/0x1d0 ? bfq_requeue_bfqq+0x70/0x70 ? check_preempt_wakeup+0x52b/0xbc0 __bfq_bfqq_expire+0x1a2/0x270 bfq_bfqq_expire+0xd16/0x2160 ? try_to_wake_up+0x4ee/0x1260 ? bfq_end_wr_async_queues+0xe0/0xe0 ? _raw_write_unlock_bh+0x60/0x60 ? _raw_spin_lock_irq+0x81/0xe0 bfq_idle_slice_timer+0x109/0x280 ? bfq_dispatch_request+0x4870/0x4870 __hrtimer_run_queues+0x37d/0x700 ? enqueue_hrtimer+0x1b0/0x1b0 ? kvm_clock_get_cycles+0xd/0x10 ? ktime_get_update_offsets_now+0x6f/0x280 hrtimer_interrupt+0x2c8/0x740 Fix the problem by checking that the parent of the two bfqqs we are merging in bfq_setup_merge() is the same.

How severe is CVE-2022-49412?

CVE-2022-49412 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.27% probability of exploitation in the next 30 days.

How do I fix CVE-2022-49412?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.