blk-iolatency: Fix memory leak on add_disk() failures
When a gendisk is successfully initialized but add_disk() fails such as when
a loop device has invalid number of minor device numbers specified,
blkcg_init_disk() is called during init and then blkcg_exit_disk() during
error handling. Unfortunately, iolatency gets initialized in the former but
doesn't get cleaned up in the latter.
This is because, in non-error cases, the cleanup is performed by
del_gendisk() calling rq_qos_exit(), the assumption being that rq_qos
policies, iolatency being one of them, can only be activated once the disk
is fully registered and visible. That assumption is true for wbt and iocost,
but not so for iolatency as it gets initialized before add_disk() is called.
It is desirable to lazy-init rq_qos policies because they are optional
features and add to hot path overhead once initialized - each IO has to walk
all the registered rq_qos policies. So, we want to switch iolatency to lazy
init too. However, that's a bigger change. As a fix for the immediate
problem, let's just add an extra call to rq_qos_exit() in blkcg_exit_disk().
This is safe because duplicate calls to rq_qos_exit() become noop's.
Metrics
Affected Vendors & Products
| Vendors | Products |
|---|---|
| Linux |
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No data.
No data.
OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.
| Vendors | Products |
|---|---|
| Linux |
|
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Wed, 08 Oct 2025 13:45:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Linux
Linux linux Kernel |
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| Vendors & Products |
Linux
Linux linux Kernel |
Wed, 08 Oct 2025 00:15:00 +0000
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| References |
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| Metrics |
threat_severity
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cvssV3_1
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Tue, 07 Oct 2025 15:30:00 +0000
| Type | Values Removed | Values Added |
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| Description | In the Linux kernel, the following vulnerability has been resolved: blk-iolatency: Fix memory leak on add_disk() failures When a gendisk is successfully initialized but add_disk() fails such as when a loop device has invalid number of minor device numbers specified, blkcg_init_disk() is called during init and then blkcg_exit_disk() during error handling. Unfortunately, iolatency gets initialized in the former but doesn't get cleaned up in the latter. This is because, in non-error cases, the cleanup is performed by del_gendisk() calling rq_qos_exit(), the assumption being that rq_qos policies, iolatency being one of them, can only be activated once the disk is fully registered and visible. That assumption is true for wbt and iocost, but not so for iolatency as it gets initialized before add_disk() is called. It is desirable to lazy-init rq_qos policies because they are optional features and add to hot path overhead once initialized - each IO has to walk all the registered rq_qos policies. So, we want to switch iolatency to lazy init too. However, that's a bigger change. As a fix for the immediate problem, let's just add an extra call to rq_qos_exit() in blkcg_exit_disk(). This is safe because duplicate calls to rq_qos_exit() become noop's. | |
| Title | blk-iolatency: Fix memory leak on add_disk() failures | |
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-10-07T15:21:12.689Z
Reserved: 2025-10-07T15:15:38.669Z
Link: CVE-2022-50550
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2025-10-07T16:15:40.790
Modified: 2025-10-08T19:38:32.610
Link: CVE-2022-50550
Redhat
OpenCVE Enrichment
Updated: 2025-10-08T13:36:36Z