CVE-2026-64099: drm/v3d: Fix use-after-free of CPU job query arrays on error path

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

drm/v3d: Fix use-after-free of CPU job query arrays on error path

The CPU job ioctl's fail label calls kvfree() on cpujob's timestamp and performance query arrays after v3djobcleanup(), which drops the job's last reference and frees cpujob. Reading cpujob at that point is a use-after-free. Also, on the early v3djobinit() failure path, it is a NULL dereference, since v3djobdeallocate() zeroes the local pointer.

In the success path, the arrays are released from the scheduler's .freejob callback, but on the error path, they are freed manually, as the job was never pushed to the scheduler. While the success path deals with this correctly, the fail path doesn't.

On top of that, the manual kvfree() calls only free the array storage; they don't drmsyncobjput() the per-query syncobjs that v3dtimestampqueryinfofree() and v3dperformancequeryinfofree() release on the success path. So the same fail path that triggers the use-after-free also leaks one syncobj reference per query.

Unify the CPU job teardown into the CPU job's kref destructor, mirroring v3drenderjobfree(). The scheduler's .freejob slot reverts to the generic v3dschedjobfree() and the fail label drops the manual kvfree() calls, leaving a single teardown path that is reached from both the scheduler and the ioctl error path. That removes the use-after-free, the NULL dereference, and the syncobj leak by construction.