blk-cgroup: fix leaks and online flag on radix_tree_insert failure
When radix_tree_insert() fails in blkg_create(), the error path has two
issues:
1. blkg->online is set to true unconditionally, even when the blkg was
never fully inserted. Move the assignment inside the success block.
2. The error path calls blkg_put() without first calling
percpu_ref_kill(). Because the refcount is still in percpu mode,
percpu_ref_put() only does this_cpu_sub() without checking for zero,
so blkg_release() is never triggered. This permanently leaks the
blkg memory, its percpu iostat, policy data, the parent blkg
reference, and the cgroup css reference — the latter preventing the
cgroup from ever being destroyed.
Fix by replacing blkg_put() with percpu_ref_kill(), matching the pattern
used in blkg_destroy().
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
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Thu, 24 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix leaks and online flag on radix_tree_insert failure When radix_tree_insert() fails in blkg_create(), the error path has two issues: 1. blkg->online is set to true unconditionally, even when the blkg was never fully inserted. Move the assignment inside the success block. 2. The error path calls blkg_put() without first calling percpu_ref_kill(). Because the refcount is still in percpu mode, percpu_ref_put() only does this_cpu_sub() without checking for zero, so blkg_release() is never triggered. This permanently leaks the blkg memory, its percpu iostat, policy data, the parent blkg reference, and the cgroup css reference — the latter preventing the cgroup from ever being destroyed. Fix by replacing blkg_put() with percpu_ref_kill(), matching the pattern used in blkg_destroy(). | |
| Title | blk-cgroup: fix leaks and online flag on radix_tree_insert failure | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-24T16:02:28.654Z
Reserved: 2026-09-18T17:59:28.789Z
Link: CVE-2026-93795
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-24T17:17:12.270
Modified: 2026-09-24T17:17:12.270
Link: CVE-2026-93795
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.