ghsa-9g9c-838j-m3cg
Vulnerability from github
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 Call Trace: 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().
{
"affected": [],
"aliases": [
"CVE-2022-50563"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-22T14:15:41Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm thin: Fix UAF in run_timer_softirq()\n\nWhen dm_resume() and dm_destroy() are concurrent, it will\nlead to UAF, as follows:\n\n BUG: KASAN: use-after-free in __run_timers+0x173/0x710\n Write of size 8 at addr ffff88816d9490f0 by task swapper/0/0\n\u003csnip\u003e\n Call Trace:\n \u003cIRQ\u003e\n dump_stack_lvl+0x73/0x9f\n print_report.cold+0x132/0xaa2\n _raw_spin_lock_irqsave+0xcd/0x160\n __run_timers+0x173/0x710\n kasan_report+0xad/0x110\n __run_timers+0x173/0x710\n __asan_store8+0x9c/0x140\n __run_timers+0x173/0x710\n call_timer_fn+0x310/0x310\n pvclock_clocksource_read+0xfa/0x250\n kvm_clock_read+0x2c/0x70\n kvm_clock_get_cycles+0xd/0x20\n ktime_get+0x5c/0x110\n lapic_next_event+0x38/0x50\n clockevents_program_event+0xf1/0x1e0\n run_timer_softirq+0x49/0x90\n __do_softirq+0x16e/0x62c\n __irq_exit_rcu+0x1fa/0x270\n irq_exit_rcu+0x12/0x20\n sysvec_apic_timer_interrupt+0x8e/0xc0\n\nOne of the concurrency UAF can be shown as below:\n\n use free\ndo_resume |\n __find_device_hash_cell |\n dm_get |\n atomic_inc(\u0026md-\u003eholders) |\n | dm_destroy\n | __dm_destroy\n | if (!dm_suspended_md(md))\n | atomic_read(\u0026md-\u003eholders)\n | msleep(1)\n dm_resume |\n __dm_resume |\n dm_table_resume_targets |\n pool_resume |\n do_waker #add delay work |\n dm_put |\n atomic_dec(\u0026md-\u003eholders) |\n | dm_table_destroy\n | pool_dtr\n | __pool_dec\n | __pool_destroy\n | destroy_workqueue\n | kfree(pool) # free pool\n time out\n__do_softirq\n run_timer_softirq # pool has already been freed\n\nThis can be easily reproduced using:\n 1. create thin-pool\n 2. dmsetup suspend pool\n 3. dmsetup resume pool\n 4. dmsetup remove_all # Concurrent with 3\n\nThe root cause of this UAF bug is that dm_resume() adds timer after\ndm_destroy() skips cancelling the timer because of suspend status.\nAfter timeout, it will call run_timer_softirq(), however pool has\nalready been freed. The concurrency UAF bug will happen.\n\nTherefore, cancelling timer again in __pool_destroy().",
"id": "GHSA-9g9c-838j-m3cg",
"modified": "2025-10-22T15:31:09Z",
"published": "2025-10-22T15:31:09Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-50563"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/34cd15d83b7206188d440b29b68084fcafde9395"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/34fe9c2251f19786a6689149a6212c6c0de1d63b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/550a4fac7ecfee5bac6a0dd772456ca62fb72f46"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7ae6aa649394e1e7f6dafb55ce0d578c0572a280"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7ee059d06a5d3c15465959e0472993e80fbe4e81"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/88430ebcbc0ec637b710b947738839848c20feff"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/94e231c9d6f2648d2f1f68e7f476e050ee0a6159"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d9971fa4d8bde63d49c743c1b32d12fbbd3a30bd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e8b8e0d2bbf7d1172c4f435621418e29ee408d46"
}
],
"schema_version": "1.4.0",
"severity": []
}
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