CVE-2026-93795

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().