CVE-2026-53126

In the Linux kernel, the following vulnerability has been resolved:

blk-cgroup: fix disk reference leak in blkcgmaybethrottle_current()

Add the missing putdisk() on the error path in blkcgmaybethrottlecurrent(). When blkcg lookup, blkg lookup, or blkgtryget() fails, the function jumps to the out label which only calls rcureadunlock() but does not release the disk reference acquired by blkcgschedulethrottle() via getdevice(). Since current->throttledisk is already set to NULL before the lookup, blkcgexit() cannot release this reference either, causing the disk to never be freed.

Restore the reference release that was present as blkputqueue() in the original code but was inadvertently dropped during the conversion from request_queue to gendisk.