[PATCH 17/17] drm/imx: fix drm_mode_config_cleanup race condition
Marco Felsch
m.felsch at pengutronix.de
Thu Feb 27 16:21:25 UTC 2020
Currently there is a race conditions if the panel can't be probed e.g.
it is not connected [1]. There where several attempts to fix this [2,3]
but non of them made it into mainline.
The problem is the combination of the component framework and the drm
framework, as Philipp already explained [1]. To fix this we need to
drop the devres-kmalloc and move the plain kmalloc to let the drm
framework free the resources upon a drm_mode_config_cleanup(). So we need
to implement a .destroy() callback for each component. We also need to
reorder the master.unbind() callback to ensure that the driver states
are accessible during a component.unbind() call. This reordering also
aligns the master.unbind() with the error-cleanup path during
master.bind().
[1] https://www.spinics.net/lists/dri-devel/msg189388.html
[2] https://lkml.org/lkml/2018/10/16/1148
[3] https://lkml.org/lkml/2019/4/2/612
Signed-off-by: Marco Felsch <m.felsch at pengutronix.de>
---
drivers/gpu/drm/imx/dw_hdmi-imx.c | 28 ++++++++++++---------
drivers/gpu/drm/imx/imx-drm-core.c | 3 ++-
drivers/gpu/drm/imx/imx-ldb.c | 34 +++++++++++++++++---------
drivers/gpu/drm/imx/imx-tve.c | 15 +++++++++---
drivers/gpu/drm/imx/ipuv3-crtc.c | 28 ++++++++++++++++++---
drivers/gpu/drm/imx/parallel-display.c | 30 ++++++++++++++++-------
6 files changed, 96 insertions(+), 42 deletions(-)
diff --git a/drivers/gpu/drm/imx/dw_hdmi-imx.c b/drivers/gpu/drm/imx/dw_hdmi-imx.c
index f22cfbf9353e..86a62796c151 100644
--- a/drivers/gpu/drm/imx/dw_hdmi-imx.c
+++ b/drivers/gpu/drm/imx/dw_hdmi-imx.c
@@ -137,6 +137,12 @@ static int dw_hdmi_imx_atomic_check(struct drm_encoder *encoder,
return 0;
}
+static void dw_hdmi_imx_encoder_destroy(struct drm_encoder *encoder)
+{
+ drm_encoder_cleanup(encoder);
+ kfree(enc_to_imx_hdmi(encoder));
+}
+
static const struct drm_encoder_helper_funcs dw_hdmi_imx_encoder_helper_funcs = {
.enable = dw_hdmi_imx_encoder_enable,
.disable = dw_hdmi_imx_encoder_disable,
@@ -144,7 +150,7 @@ static const struct drm_encoder_helper_funcs dw_hdmi_imx_encoder_helper_funcs =
};
static const struct drm_encoder_funcs dw_hdmi_imx_encoder_funcs = {
- .destroy = drm_encoder_cleanup,
+ .destroy = dw_hdmi_imx_encoder_destroy,
};
static enum drm_mode_status
@@ -212,7 +218,7 @@ static int dw_hdmi_imx_bind(struct device *dev, struct device *master,
if (!pdev->dev.of_node)
return -ENODEV;
- hdmi = devm_kzalloc(&pdev->dev, sizeof(*hdmi), GFP_KERNEL);
+ hdmi = kzalloc(sizeof(*hdmi), GFP_KERNEL);
if (!hdmi)
return -ENOMEM;
@@ -228,12 +234,16 @@ static int dw_hdmi_imx_bind(struct device *dev, struct device *master,
* not been registered yet. Defer probing, and hope that
* the required CRTC is added later.
*/
- if (encoder->possible_crtcs == 0)
+ if (encoder->possible_crtcs == 0) {
+ kfree(hdmi);
return -EPROBE_DEFER;
+ }
ret = dw_hdmi_imx_parse_dt(hdmi);
- if (ret < 0)
+ if (ret < 0) {
+ kfree(hdmi);
return ret;
+ }
drm_encoder_helper_add(encoder, &dw_hdmi_imx_encoder_helper_funcs);
drm_encoder_init(drm, encoder, &dw_hdmi_imx_encoder_funcs,
@@ -242,15 +252,9 @@ static int dw_hdmi_imx_bind(struct device *dev, struct device *master,
platform_set_drvdata(pdev, hdmi);
hdmi->hdmi = dw_hdmi_bind(pdev, encoder, plat_data);
-
- /*
- * If dw_hdmi_bind() fails we'll never call dw_hdmi_unbind(),
- * which would have called the encoder cleanup. Do it manually.
- */
- if (IS_ERR(hdmi->hdmi)) {
+ /* Don't call kfree() here, this is done by the .destroy() handler. */
+ if (IS_ERR(hdmi->hdmi))
ret = PTR_ERR(hdmi->hdmi);
- drm_encoder_cleanup(encoder);
- }
return ret;
}
diff --git a/drivers/gpu/drm/imx/imx-drm-core.c b/drivers/gpu/drm/imx/imx-drm-core.c
index 9979547ca883..feab6eb9e7e5 100644
--- a/drivers/gpu/drm/imx/imx-drm-core.c
+++ b/drivers/gpu/drm/imx/imx-drm-core.c
@@ -275,9 +275,10 @@ static void imx_drm_unbind(struct device *dev)
drm_kms_helper_poll_fini(drm);
+ component_unbind_all(drm->dev, drm);
+
drm_mode_config_cleanup(drm);
- component_unbind_all(drm->dev, drm);
dev_set_drvdata(dev, NULL);
drm_dev_put(drm);
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index 5e6c1b09dbfa..4a5d31da592a 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -140,6 +140,8 @@ static void imx_ldb_connector_destroy(struct drm_connector *connector)
i2c_put_adapter(imx_ldb_con->ddc);
/* avoid dangling pointers */
imx_ldb_con->ldb_channel = NULL;
+ kfree(imx_ldb_con->edid);
+ kfree(imx_ldb_con);
}
static int imx_ldb_connector_get_modes(struct drm_connector *connector)
@@ -184,6 +186,7 @@ static void imx_ldb_encoder_destroy(struct drm_encoder *encoder)
drm_encoder_cleanup(encoder);
/* avoid dangling pointers */
channel->ldb = NULL;
+ kfree(channel);
}
static void imx_ldb_set_clock(struct imx_ldb *ldb, int mux, int chno,
@@ -502,9 +505,8 @@ static int imx_ldb_panel_ddc(struct device *dev,
edidp = of_get_property(child, "edid",
&connector->edid_len);
if (edidp) {
- connector->edid = devm_kmemdup(dev, edidp,
- connector->edid_len,
- GFP_KERNEL);
+ connector->edid = kmemdup(edidp, connector->edid_len,
+ GFP_KERNEL);
} else if (!channel->panel) {
/* fallback to display-timings node */
ret = of_get_drm_display_mode(child,
@@ -525,7 +527,7 @@ static int imx_ldb_setup_channel(struct device *dev,
int channel_number)
{
struct imx_ldb_channel *channel;
- struct imx_ldb_connector *imx_ldb_con;
+ struct imx_ldb_connector *imx_ldb_con = NULL;
struct drm_encoder *encoder;
struct drm_connector *connector = NULL;
int bus_format;
@@ -537,7 +539,7 @@ static int imx_ldb_setup_channel(struct device *dev,
* 3) Register it with the DRM framework
* 4) Attach bridge or connector to encoder
*/
- channel = devm_kzalloc(dev, sizeof(*channel), GFP_KERNEL);
+ channel = kzalloc(sizeof(*channel), GFP_KERNEL);
if (!channel)
return -ENOMEM;
@@ -554,17 +556,19 @@ static int imx_ldb_setup_channel(struct device *dev,
ldb->lvds_mux ? 4 : 2, 0,
&channel->panel, &channel->bridge);
if (ret && ret != -ENODEV)
- return ret;
+ goto err_free;
/* panel ddc only if there is no bridge */
if (!channel->bridge) {
- imx_ldb_con = devm_kzalloc(dev, sizeof(*connector), GFP_KERNEL);
- if (!imx_ldb_con)
- return -ENOMEM;
+ imx_ldb_con = kzalloc(sizeof(*connector), GFP_KERNEL);
+ if (!imx_ldb_con) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
ret = imx_ldb_panel_ddc(dev, channel, imx_ldb_con, child);
if (ret)
- return ret;
+ goto err_free;
imx_ldb_con->ldb_channel = channel;
connector = &imx_ldb_con->connector;
@@ -628,7 +632,7 @@ static int imx_ldb_setup_channel(struct device *dev,
ret = drm_bridge_attach(encoder, channel->bridge, NULL);
if (ret) {
DRM_ERROR("Failed to initialize bridge with drm\n");
- goto err_put_ddc;
+ goto err_out;
}
} else {
drm_connector_attach_encoder(connector, encoder);
@@ -637,7 +641,7 @@ static int imx_ldb_setup_channel(struct device *dev,
if (channel->panel) {
ret = drm_panel_attach(channel->panel, connector);
if (ret)
- goto err_put_ddc;
+ goto err_out;
}
return 0;
@@ -645,6 +649,12 @@ static int imx_ldb_setup_channel(struct device *dev,
err_put_ddc:
if (imx_ldb_con)
i2c_put_adapter(imx_ldb_con->ddc);
+err_free:
+ if (imx_ldb_con)
+ kfree(imx_ldb_con->edid);
+ kfree(imx_ldb_con);
+ kfree(channel);
+err_out:
return ret;
}
diff --git a/drivers/gpu/drm/imx/imx-tve.c b/drivers/gpu/drm/imx/imx-tve.c
index a7a05c47f68b..15ff5f35ff0e 100644
--- a/drivers/gpu/drm/imx/imx-tve.c
+++ b/drivers/gpu/drm/imx/imx-tve.c
@@ -241,6 +241,7 @@ static void imx_tve_connector_destroy(struct drm_connector *connector)
i2c_put_adapter(tvec->ddc);
/* avoid dangling pointers */
tvec->tve = NULL;
+ kfree(tvec);
}
static int imx_tve_connector_get_modes(struct drm_connector *connector)
@@ -292,6 +293,7 @@ static void imx_tve_encoder_destroy(struct drm_encoder *encoder)
drm_encoder_cleanup(encoder);
/* avoid dangling pointers */
tvee->tve = NULL;
+ kfree(tvee);
}
static void imx_tve_encoder_mode_set(struct drm_encoder *encoder,
@@ -577,13 +579,15 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
struct imx_tve_connector *tvec;
int ret;
- tvee = devm_kzalloc(dev, sizeof(*tvee), GFP_KERNEL);
+ tvee = kzalloc(sizeof(*tvee), GFP_KERNEL);
if (!tvee)
return -ENOMEM;
- tvec = devm_kzalloc(dev, sizeof(*tvec), GFP_KERNEL);
- if (!tvec)
- return -ENOMEM;
+ tvec = kzalloc(sizeof(*tvec), GFP_KERNEL);
+ if (!tvec) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
tvee->tve = imx_tve;
tvec->tve = imx_tve;
@@ -602,6 +606,9 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
err_put_ddc:
i2c_put_adapter(tvec->ddc);
+err_free:
+ kfree(tvec);
+ kfree(tvee);
return ret;
}
diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3-crtc.c
index 63c0284f8b3c..2d24677f7fef 100644
--- a/drivers/gpu/drm/imx/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3-crtc.c
@@ -105,6 +105,12 @@ static void ipu_crtc_atomic_disable(struct drm_crtc *crtc,
spin_unlock_irq(&crtc->dev->event_lock);
}
+static void imx_drm_crtc_destroy(struct drm_crtc *crtc)
+{
+ drm_crtc_cleanup(crtc);
+ kfree(to_ipu_crtc(crtc));
+}
+
static void imx_drm_crtc_reset(struct drm_crtc *crtc)
{
struct imx_crtc_state *state;
@@ -166,7 +172,7 @@ static void ipu_disable_vblank(struct drm_crtc *crtc)
static const struct drm_crtc_funcs ipu_crtc_funcs = {
.set_config = drm_atomic_helper_set_config,
- .destroy = drm_crtc_cleanup,
+ .destroy = imx_drm_crtc_destroy,
.page_flip = drm_atomic_helper_page_flip,
.reset = imx_drm_crtc_reset,
.atomic_duplicate_state = imx_drm_crtc_duplicate_state,
@@ -357,7 +363,8 @@ static int ipu_get_resources(struct ipu_crtc *ipu_crtc,
}
static int ipu_crtc_init(struct ipu_crtc *ipu_crtc,
- struct ipu_client_platformdata *pdata, struct drm_device *drm)
+ struct ipu_client_platformdata *pdata,
+ struct drm_device *drm)
{
struct ipu_soc *ipu = dev_get_drvdata(ipu_crtc->dev->parent);
struct drm_crtc *crtc = &ipu_crtc->base;
@@ -437,10 +444,11 @@ static int ipu_drm_bind(struct device *dev, struct device *master, void *data)
{
struct ipu_client_platformdata *pdata = dev->platform_data;
struct drm_device *drm = data;
+ struct drm_crtc *registered_crtc = NULL;
struct ipu_crtc *ipu_crtc;
int ret;
- ipu_crtc = devm_kzalloc(dev, sizeof(*ipu_crtc), GFP_KERNEL);
+ ipu_crtc = kzalloc(sizeof(*ipu_crtc), GFP_KERNEL);
if (!ipu_crtc)
return -ENOMEM;
@@ -448,11 +456,23 @@ static int ipu_drm_bind(struct device *dev, struct device *master, void *data)
ret = ipu_crtc_init(ipu_crtc, pdata, drm);
if (ret)
- return ret;
+ goto err;
dev_set_drvdata(dev, ipu_crtc);
return 0;
+
+err:
+ drm_for_each_crtc(registered_crtc, drm) {
+ /*
+ * The crtc was registered with the drm core framework if we
+ * enter here. So let the core .destroy() helper cleanup the
+ * code.
+ */
+ return ret;
+ }
+ kfree(ipu_crtc);
+ return ret;
}
static void ipu_drm_unbind(struct device *dev, struct device *master,
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c
index 78703b15c7cf..3e247383a498 100644
--- a/drivers/gpu/drm/imx/parallel-display.c
+++ b/drivers/gpu/drm/imx/parallel-display.c
@@ -55,6 +55,8 @@ static void imx_pd_connector_destroy(struct drm_connector *connector)
imx_drm_connector_destroy(connector);
/* avoid dangling pointer */
imxpc->imxpd = NULL;
+ kfree(imxpc->edid);
+ kfree(imxpc);
}
static int imx_pd_connector_get_modes(struct drm_connector *connector)
@@ -102,6 +104,7 @@ static void imx_pd_encoder_destroy(struct drm_encoder *encoder)
if (imxpd->panel)
drm_panel_detach(imxpd->panel);
drm_encoder_cleanup(encoder);
+ kfree(imxpd);
}
static void imx_pd_encoder_enable(struct drm_encoder *encoder)
@@ -225,31 +228,32 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
struct device_node *np = dev->of_node;
const u8 *edidp;
struct imx_parallel_display *imxpd;
- struct imx_parallel_connector *imxpc;
+ struct imx_parallel_connector *imxpc = NULL;
int ret;
u32 bus_format = 0;
const char *fmt;
- imxpd = devm_kzalloc(dev, sizeof(*imxpd), GFP_KERNEL);
+ imxpd = kzalloc(sizeof(*imxpd), GFP_KERNEL);
if (!imxpd)
return -ENOMEM;
/* port at 1 is the output port */
ret = drm_of_find_panel_or_bridge(np, 1, 0, &imxpd->panel, &imxpd->bridge);
if (ret && ret != -ENODEV)
- return ret;
+ goto err_free;
if (!imxpd->bridge) {
- imxpc = devm_kzalloc(dev, sizeof(*imxpc), GFP_KERNEL);
- if (!imxpc)
- return -ENOMEM;
+ imxpc = kzalloc(sizeof(*imxpc), GFP_KERNEL);
+ if (!imxpc) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
imxpc->imxpd = imxpd;
edidp = of_get_property(np, "edid", &imxpc->edid_len);
if (edidp)
- imxpc->edid = devm_kmemdup(dev, edidp, imxpc->edid_len,
- GFP_KERNEL);
+ imxpc->edid = kmemdup(edidp, imxpc->edid_len, GFP_KERNEL);
}
ret = of_property_read_string(np, "interface-pix-fmt", &fmt);
@@ -269,9 +273,17 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
ret = imx_pd_register(drm, imxpd, imxpc);
if (ret)
- return ret;
+ goto err_free;
return imx_pd_attach(drm, imxpd, imxpc);
+
+err_free:
+ if (imxpc)
+ kfree(imxpc->edid);
+ kfree(imxpc);
+ kfree(imxpd);
+
+ return ret;
}
static const struct component_ops imx_pd_ops = {
--
2.20.1
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