CVE-2022-49412: bfq: Avoid merging queues with different parents
First published: Wed Feb 26 2025(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | ||
| Linux Kernel | <5.4.198 | |
| Linux Kernel | >=5.5<5.10.121 | |
| Linux Kernel | >=5.13<5.15.46 | |
| Linux Kernel | >=5.16<5.17.14 | |
| Linux Kernel | >=5.18<5.18.3 |
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Reference Links
- https://git.kernel.org/stable/c/97be7d13fbd4001eeab49b1be6399f23a8c66160
- https://git.kernel.org/stable/c/7d172b9dc913e161d8ff88770eea01701ff553de
- https://git.kernel.org/stable/c/5ee21edaed09e6b25f2c007b3f326752bc89bacf
- https://git.kernel.org/stable/c/a16c65cca7d2c7ff965fdd3adc8df2156529caf1
- https://git.kernel.org/stable/c/8abc8763b11c35e03cc91d59fd0cd28d39f88ca9
- https://git.kernel.org/stable/c/c1cee4ab36acef271be9101590756ed0c0c374d9
Frequently Asked Questions
What is the severity of CVE-2022-49412?
CVE-2022-49412 has a medium severity level due to potential issues with queue merging in the Linux kernel.
Which versions of the Linux kernel are affected by CVE-2022-49412?
CVE-2022-49412 affects Linux kernel versions from 5.5 up to, but not including, 5.4.198, as well as various other specific versions.
How do I fix CVE-2022-49412?
To fix CVE-2022-49412, update your Linux kernel to a version that is greater than 5.18.3.
What are the risks associated with CVE-2022-49412?
The risks associated with CVE-2022-49412 include potential system instability and increased vulnerability to attacks that exploit queue management flaws.
Is there a workaround for CVE-2022-49412?
There are no reliable workarounds for CVE-2022-49412; updating the kernel is recommended for mitigation.
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