linux-kernel - [PATCH] drm/v3d: fix reference leak when pm_runtime_get

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Date:   Tue, 1 Dec 2020 20:56:32 +0800
From:   Qinglang Miao <miaoqinglang@...wei.com>
To:     Eric Anholt <eric@...olt.net>, David Airlie <airlied@...ux.ie>,
        "Daniel Vetter" <daniel@...ll.ch>
CC:     <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        Qinglang Miao <miaoqinglang@...wei.com>
Subject: [PATCH] drm/v3d: fix reference leak when pm_runtime_get_sync fails

The PM reference count is not expected to be incremented on
return in functions v3d_get_param_ioctl and v3d_job_init.

However, pm_runtime_get_sync will increment the PM reference
count even failed. Forgetting to putting operation will result
in a reference leak here.

Replace it with pm_runtime_resume_and_get to keep usage
counter balanced.

Fixes: 57692c94dcbe ("drm/v3d: Introduce a new DRM driver for Broadcom V3D V3.x+")
Fixes: 935f3d88434b ("drm/v3d: Make sure the GPU is on when measuring clocks.")
Reported-by: Hulk Robot <hulkci@...wei.com>
Signed-off-by: Qinglang Miao <miaoqinglang@...wei.com>
---
 drivers/gpu/drm/v3d/v3d_debugfs.c | 4 ++--
 drivers/gpu/drm/v3d/v3d_gem.c     | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/v3d/v3d_debugfs.c b/drivers/gpu/drm/v3d/v3d_debugfs.c
index e76b24bb8..91ceed774 100644
--- a/drivers/gpu/drm/v3d/v3d_debugfs.c
+++ b/drivers/gpu/drm/v3d/v3d_debugfs.c
@@ -132,7 +132,7 @@ static int v3d_v3d_debugfs_ident(struct seq_file *m, void *unused)
 	u32 ident0, ident1, ident2, ident3, cores;
 	int ret, core;
 
-	ret = pm_runtime_get_sync(v3d->drm.dev);
+	ret = pm_runtime_resume_and_get(v3d->drm.dev);
 	if (ret < 0)
 		return ret;
 
@@ -219,7 +219,7 @@ static int v3d_measure_clock(struct seq_file *m, void *unused)
 	int measure_ms = 1000;
 	int ret;
 
-	ret = pm_runtime_get_sync(v3d->drm.dev);
+	ret = pm_runtime_resume_and_get(v3d->drm.dev);
 	if (ret < 0)
 		return ret;
 
diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
index 182c58652..765683569 100644
--- a/drivers/gpu/drm/v3d/v3d_gem.c
+++ b/drivers/gpu/drm/v3d/v3d_gem.c
@@ -439,7 +439,7 @@ v3d_job_init(struct v3d_dev *v3d, struct drm_file *file_priv,
 	job->v3d = v3d;
 	job->free = free;
 
-	ret = pm_runtime_get_sync(v3d->drm.dev);
+	ret = pm_runtime_resume_and_get(v3d->drm.dev);
 	if (ret < 0)
 		return ret;
 
-- 
2.23.0