CVE-2026-89801

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

drm/nouveau/uvmm: fix premature region free on failed OP_UNMAP_SPARSE

In nouveau_uvmm_bind_job_submit()'s OP_UNMAP_SPARSE arm, op->reg is set

from nouveau_uvma_region_find(), which only looks the region up and takes

no reference; a region's sole reference is its membership in

uvmm->region_mt. Two failure paths leave op->reg set: the -ENOENT check

when the region is busy, and the drm_gpuvm_sm_unmap_ops_create() failure.

The sibling nouveau_uvmm_sm_unmap_prepare() failure just below clears

op->reg; these two do not.

unwind_continue steps back one op, so the failing op is skipped by the

unwind loop and its op->reg stays set. nouveau_uvmm_bind_job_cleanup()

then enters its if (op->reg) branch and calls nouveau_uvma_region_remove()

and nouveau_uvma_region_put() on it, dropping the tree's sole reference

and freeing a region this job never created. The comment above the

cleanup loop documents the broken invariant: op->reg must be NULL on

submit failure.

This frees a live region on an unrelated failure, reachable single-job

when drm_gpuvm_sm_unmap_ops_create() returns -ENOMEM; if another job owns

the same region, its cleanup then removes and puts the freed region, a

use-after-free. Clear op->reg on both failure paths.