FAILED: patch "[PATCH] drm/msm/dsi: Fix VM leak in dsi_tx_buf_alloc_6g()" failed to apply to 6.6-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x ab91ba61871a896ca2ecc6e048d80a152136da44
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107053059-failed-6.6-ab91ba61871a@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From ab91ba61871a896ca2ecc6e048d80a152136da44 Mon Sep 17 00:00:00 2001
From: Wentao Liang <vulab@iscas.ac.cn>
Date: Wed, 16 Sep 2026 17:57:38 +0000
Subject: [PATCH] drm/msm/dsi: Fix VM leak in dsi_tx_buf_alloc_6g()

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>
---
 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 b292dfd266d17..d92659d80f172 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1254,6 +1254,8 @@ int dsi_tx_buf_alloc_6g(struct msm_dsi_host *msm_host, int size)
 
 	if (IS_ERR(data)) {
 		msm_host->tx_gem_obj = NULL;
+		drm_gpuvm_put(msm_host->vm);
+		msm_host->vm = NULL;
 		return PTR_ERR(data);
 	}
 
-- 
2.53.0