CVE-2022-50563
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-22

Last updated on: 2025-10-22

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: dm thin: Fix UAF in run_timer_softirq() When dm_resume() and dm_destroy() are concurrent, it will lead to UAF, as follows: BUG: KASAN: use-after-free in __run_timers+0x173/0x710 Write of size 8 at addr ffff88816d9490f0 by task swapper/0/0 <snip> Call Trace: <IRQ> dump_stack_lvl+0x73/0x9f print_report.cold+0x132/0xaa2 _raw_spin_lock_irqsave+0xcd/0x160 __run_timers+0x173/0x710 kasan_report+0xad/0x110 __run_timers+0x173/0x710 __asan_store8+0x9c/0x140 __run_timers+0x173/0x710 call_timer_fn+0x310/0x310 pvclock_clocksource_read+0xfa/0x250 kvm_clock_read+0x2c/0x70 kvm_clock_get_cycles+0xd/0x20 ktime_get+0x5c/0x110 lapic_next_event+0x38/0x50 clockevents_program_event+0xf1/0x1e0 run_timer_softirq+0x49/0x90 __do_softirq+0x16e/0x62c __irq_exit_rcu+0x1fa/0x270 irq_exit_rcu+0x12/0x20 sysvec_apic_timer_interrupt+0x8e/0xc0 One of the concurrency UAF can be shown as below: use free do_resume | __find_device_hash_cell | dm_get | atomic_inc(&md->holders) | | dm_destroy | __dm_destroy | if (!dm_suspended_md(md)) | atomic_read(&md->holders) | msleep(1) dm_resume | __dm_resume | dm_table_resume_targets | pool_resume | do_waker #add delay work | dm_put | atomic_dec(&md->holders) | | dm_table_destroy | pool_dtr | __pool_dec | __pool_destroy | destroy_workqueue | kfree(pool) # free pool time out __do_softirq run_timer_softirq # pool has already been freed This can be easily reproduced using: 1. create thin-pool 2. dmsetup suspend pool 3. dmsetup resume pool 4. dmsetup remove_all # Concurrent with 3 The root cause of this UAF bug is that dm_resume() adds timer after dm_destroy() skips cancelling the timer because of suspend status. After timeout, it will call run_timer_softirq(), however pool has already been freed. The concurrency UAF bug will happen. Therefore, cancelling timer again in __pool_destroy().
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2025-10-22
Last Modified
2025-10-22
Generated
2026-05-07
AI Q&A
2025-10-22
EPSS Evaluated
2026-05-05
NVD
CVE-2022-50563
EUVD
EUVD-2022-55665
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux kernel *
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a use-after-free (UAF) bug in the Linux kernel's device mapper thin provisioning (dm thin) subsystem. It occurs when dm_resume() and dm_destroy() functions run concurrently, leading to a timer being added after the associated pool has already been freed. When the timer expires, it triggers run_timer_softirq(), which accesses the freed memory, causing a use-after-free error. This happens because dm_destroy() skips cancelling the timer due to the suspend status, and dm_resume() adds the timer again, resulting in a race condition and memory corruption.


How can this vulnerability impact me? :

This vulnerability can lead to kernel crashes or undefined behavior due to use-after-free memory access. Exploiting this flaw could potentially allow an attacker to execute arbitrary code in kernel space or cause denial of service by crashing the system, impacting system stability and security.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, avoid concurrently running dm_resume() and dm_destroy() operations on thin-pools. Specifically, do not resume a thin-pool while simultaneously removing it. Follow the sequence carefully: create the thin-pool, suspend it, resume it, and only then remove it after ensuring no concurrent resume operation is ongoing. Additionally, apply any available patches that fix the use-after-free by cancelling timers properly in __pool_destroy().


Ask Our AI Assistant
Need more information? Ask your question to get an AI reply (Powered by our expertise)
0/70
EPSS Chart