linux-kernel - [PATCH] drm/vc4: fix ref count leak in vc4_vec_encoder

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Date:   Sun, 14 Jun 2020 01:59:18 -0500
From:   Navid Emamdoost <navid.emamdoost@...il.com>
To:     Eric Anholt <eric@...olt.net>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:     emamd001@....edu, wu000273@....edu, kjlu@....edu, smccaman@....edu,
        Navid Emamdoost <navid.emamdoost@...il.com>
Subject: [PATCH] drm/vc4: fix ref count leak in vc4_vec_encoder_enable

in vc4_vec_encoder_enable, the call to pm_runtime_get_sync increments
the counter even in case of failure, leading to incorrect
ref count. In case of failure, decrement the ref count before returning.

Signed-off-by: Navid Emamdoost <navid.emamdoost@...il.com>
---
 drivers/gpu/drm/vc4/vc4_vec.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_vec.c b/drivers/gpu/drm/vc4/vc4_vec.c
index bd5b8eb58b18..706fdc7758f9 100644
--- a/drivers/gpu/drm/vc4/vc4_vec.c
+++ b/drivers/gpu/drm/vc4/vc4_vec.c
@@ -406,7 +406,7 @@ static void vc4_vec_encoder_enable(struct drm_encoder *encoder)
 	ret = pm_runtime_get_sync(&vec->pdev->dev);
 	if (ret < 0) {
 		DRM_ERROR("Failed to retain power domain: %d\n", ret);
-		return;
+		goto out;
 	}
 
 	/*
@@ -419,13 +419,13 @@ static void vc4_vec_encoder_enable(struct drm_encoder *encoder)
 	ret = clk_set_rate(vec->clock, 108000000);
 	if (ret) {
 		DRM_ERROR("Failed to set clock rate: %d\n", ret);
-		return;
+		goto out;
 	}
 
 	ret = clk_prepare_enable(vec->clock);
 	if (ret) {
 		DRM_ERROR("Failed to turn on core clock: %d\n", ret);
-		return;
+		goto out;
 	}
 
 	/* Reset the different blocks */
@@ -464,6 +464,8 @@ static void vc4_vec_encoder_enable(struct drm_encoder *encoder)
 	VEC_WRITE(VEC_DAC_MISC,
 		  VEC_DAC_MISC_VID_ACT | VEC_DAC_MISC_DAC_RST_N);
 	VEC_WRITE(VEC_CFG, VEC_CFG_VEC_EN);
+out:
+	pm_runtime_put(&vec->pdev->dev);
 }
 
 
-- 
2.17.1