[PATCH 6.12.y] drm/msm/dsi: Fix VM leak in dsi_tx_buf_alloc_6g()

[Sasha Levin <sashal@kernel.org>]

From: Wentao Liang <vulab@iscas.ac.cn>

[ Upstream commit ab91ba61871a896ca2ecc6e048d80a152136da44 ]

dsi_tx_buf_alloc_6g() takes a reference to the kms VM with
drm_gpuvm_get() and stores it in msm_host->vm.  If
msm_gem_kernel_new() fails, the function returns early without
dropping that reference.  Since msm_host->tx_gem_obj is cleared on
the error path, msm_dsi_tx_buf_free() will never see a non-NULL
tx_gem_obj and thus never calls drm_gpuvm_put(), leaking the VM
reference.

Drop the VM reference and clear msm_host->vm on the error path.

Fixes: 5e05be782645 ("drm/msm/dsi: free TX buffer in unbind")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Reviewed-by: Rob Clark <rob.clark@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/754332/
Link: https://lore.kernel.org/r/20260916175738.2089950-1-vulab@iscas.ac.cn
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
[ sashal: Adapted GPU VM cleanup to use the older msm_gem_address_space_put() API and msm_host->aspace member. ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index cd605c75cef8e..ebd9dfca6459b 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1205,6 +1205,8 @@ int dsi_tx_buf_alloc_6g(struct msm_dsi_host *msm_host, int size)
 
 	if (IS_ERR(data)) {
 		msm_host->tx_gem_obj = NULL;
+		msm_gem_address_space_put(msm_host->aspace);
+		msm_host->aspace = NULL;
 		return PTR_ERR(data);
 	}
 
-- 
2.53.0