[PATCH v2 3/3] drm/nouveau/uvmm: clear the dirty flag when unwinding an OP_UNMAP_SPARSE

[Zhenhao Wan]

A successful OP_UNMAP_SPARSE marks its region dirty with
nouveau_uvma_region_dirty() and defers the teardown to
nouveau_uvmm_bind_job_cleanup(); it does not remove the region from
uvmm->region_mt.

If a later op in the job fails, the unwind path never clears reg->dirty
(set in one place, cleared nowhere) and sets op->reg = NULL, so cleanup
skips the teardown. The region is left in the tree with dirty set and its
completion never signalled. Later binds over that range then fail
permanently -- -ENOENT or -EINVAL from the dirty checks, or an unkillable
wait_for_completion() in bind_validate_region() -- for the lifetime of
the uvmm.

Clear reg->dirty when the unwind reverts the sparse unmap, restoring the
region to the state it was found in.

Fixes: b88baab82871 ("drm/nouveau: implement new VM_BIND uAPI")
Reported-by: Yuhao Jiang <danisjiang@xxxxxxxxx>
Assisted-by: Claude:claude-opus-5
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Zhenhao Wan <whi4ed0g@xxxxxxxxx>
---
 drivers/gpu/drm/nouveau/nouveau_uvmm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
index 3412200b21fd..76ab377f0e2c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c
@@ -1475,6 +1475,7 @@ nouveau_uvmm_bind_job_submit(struct nouveau_job *job,
 						    op->va.range);
 			break;
 		case OP_UNMAP_SPARSE:
+			op->reg->dirty = false;
 			__nouveau_uvma_region_insert(uvmm, op->reg);
 			nouveau_uvmm_sm_unmap_prepare_unwind(uvmm, &op->new,
 							     op->ops);

-- 
2.34.1