linux-kernel - [PATCH 01/10] Revert "drm/msm: Add missing check and destroy for alloc_ordered

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Date:   Mon,  6 Mar 2023 11:07:13 +0100
From:   Johan Hovold <johan+linaro@...nel.org>
To:     Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org,
        Johan Hovold <johan+linaro@...nel.org>,
        Jiasheng Jiang <jiasheng@...as.ac.cn>
Subject: [PATCH 01/10] Revert "drm/msm: Add missing check and destroy for alloc_ordered_workqueue"

This reverts commit 643b7d0869cc7f1f7a5ac7ca6bd25d88f54e31d0.

A recent patch that tried to fix up the msm_drm_init() paths with
respect to the workqueue but only ended up making things worse:

First, the newly added calls to msm_drm_uninit() on early errors would
trigger NULL-pointer dereferences, for example, as the kms pointer would
not have been initialised. (Note that these paths were also modified by
a second broken error handling patch which in effect cancelled out this
part when merged.)

Second, the newly added allocation sanity check would still leak the
previously allocated drm device.

Instead of trying to salvage what was badly broken (and clearly not
tested), let's revert the bad commit so that clean and backportable
fixes can be added in its place.

Fixes: 643b7d0869cc ("drm/msm: Add missing check and destroy for alloc_ordered_workqueue")
Cc: Jiasheng Jiang <jiasheng@...as.ac.cn>
Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
---
 drivers/gpu/drm/msm/msm_drv.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index aca48c868c14..b7f5a78eadd4 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -420,8 +420,6 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
 	priv->dev = ddev;

 	priv->wq = alloc_ordered_workqueue("msm", 0);
-	if (!priv->wq)
-		return -ENOMEM;

 	INIT_LIST_HEAD(&priv->objects);
 	mutex_init(&priv->obj_lock);
-- 
2.39.2