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

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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.

Fixes: b88baab828 ("drm/nouveau: implement new VM_BIND uAPI")
Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Assisted-by: Claude:claude-opus-5
Cc: stable@vger.kernel.org
Signed-off-by: Zhenhao Wan <whi4ed0g@gmail.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patch.msgid.link/20260811-nouveau-uvmm-vmbind-fixes-v2-2-aaee4b395d04@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Zhenhao Wan 2026-08-11 16:46:29 +08:00 committed by Danilo Krummrich
parent 412a6ceb56
commit ccf930812f
1 changed files with 2 additions and 0 deletions
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2
drivers/gpu/drm/nouveau/nouveau_uvmm.c
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@ -1319,6 +1319,7 @@ nouveau_uvmm_bind_job_submit(struct nouveau_job *job,
op->va.range);
if (!op->reg || op->reg->dirty) {
ret = -ENOENT;
op->reg = NULL;
goto unwind_continue;
}
@ -1327,6 +1328,7 @@ nouveau_uvmm_bind_job_submit(struct nouveau_job *job,
op->va.range);
if (IS_ERR(op->ops)) {
ret = PTR_ERR(op->ops);
op->reg = NULL;
goto unwind_continue;
}