linux-kernel - [ 047/105] drm/radeon: Dont destroy I2C Bus Rec in radeon_ext_tmds_enc

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Message-Id: <20121028231551.559258973@decadent.org.uk>
Date:	Sun, 28 Oct 2012 23:16:23 +0000
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Egbert Eich <eich@...e.de>,
	Alex Deucher <alexander.deucher@....com>
Subject: [ 047/105] drm/radeon: Dont destroy I2C Bus Rec in
 radeon_ext_tmds_enc_destroy().

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Egbert Eich <eich@...e.de>

commit 082918471139b07964967cfe5f70230909c82ae1 upstream.

radeon_i2c_fini() walks thru the list of I2C bus recs rdev->i2c_bus[]
to destroy each of them.
radeon_ext_tmds_enc_destroy() however also has code to destroy it's
associated I2C bus rec which has been obtained by radeon_i2c_lookup()
and is therefore also in the i2c_bus[] list.
This causes a double free resulting in a kernel panic when unloading
the radeon driver.
Removing destroy code from radeon_ext_tmds_enc_destroy() fixes this
problem.

agd5f: fix compiler warning

Signed-off-by: Egbert Eich <eich@...e.de>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/gpu/drm/radeon/radeon_legacy_encoders.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_legacy_encoders.c b/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
index fb15b62..a13ad9d 100644
--- a/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
@@ -991,11 +991,7 @@ static void radeon_legacy_tmds_ext_mode_set(struct drm_encoder *encoder,
 static void radeon_ext_tmds_enc_destroy(struct drm_encoder *encoder)
 {
 	struct radeon_encoder *radeon_encoder = to_radeon_encoder(encoder);
-	struct radeon_encoder_ext_tmds *tmds = radeon_encoder->enc_priv;
-	if (tmds) {
-		if (tmds->i2c_bus)
-			radeon_i2c_destroy(tmds->i2c_bus);
-	}
+	/* don't destroy the i2c bus record here, this will be done in radeon_i2c_fini */
 	kfree(radeon_encoder->enc_priv);
 	drm_encoder_cleanup(encoder);
 	kfree(radeon_encoder);


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