CVE-2026-93795
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().
How to fix
- Linux Linux0f840db042caee9d2f3dcdcf97d6674f6e4c1e30, f53945d7c712efe63fadbcc5ffed6370871fd0d3, ada8270ccdb6f212da5eb22614c28ea418746a4a, c3650be82ef6e7af13b79b2d10a7363bdf54aa7f, 6e85f02d45b5977c0326a8d854c6db878aa6b34a, 4c0d150fb98ea40760611979f4e664c244b20966, dbbca20764382b4d411ec2918f4e278ffe547acc or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 7fcf2b033b84e261dca283bc2911aaea4b07b525 ≤ v < 0f840db042caee9d2f3dcdcf97d6674f6e4c1e30, 7fcf2b033b84e261dca283bc2911aaea4b07b525 ≤ v < f53945d7c712efe63fadbcc5ffed6370871fd0d3, 7fcf2b033b84e261dca283bc2911aaea4b07b525 ≤ v < ada8270ccdb6f212da5eb22614c28ea418746a4a, 7fcf2b033b84e261dca283bc2911aaea4b07b525 ≤ v < c3650be82ef6e7af13b79b2d10a7363bdf54aa7f, 7fcf2b033b84e261dca283bc2911aaea4b07b525 ≤ v < 6e85f02d45b5977c0326a8d854c6db878aa6b34a, 7fcf2b033b84e261dca283bc2911aaea4b07b525 ≤ v < 4c0d150fb98ea40760611979f4e664c244b20966, 7fcf2b033b84e261dca283bc2911aaea4b07b525 ≤ v < dbbca20764382b4d411ec2918f4e278ffe547acc, 5.0 | 0f840db042caee9d2f3dcdcf97d6674f6e4c1e30, f53945d7c712efe63fadbcc5ffed6370871fd0d3, ada8270ccdb6f212da5eb22614c28ea418746a4a, c3650be82ef6e7af13b79b2d10a7363bdf54aa7f, 6e85f02d45b5977c0326a8d854c6db878aa6b34a, 4c0d150fb98ea40760611979f4e664c244b20966, dbbca20764382b4d411ec2918f4e278ffe547acc |
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