| Message ID | 1443775171-31600-1-git-send-email-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 2 Oct 2015, Daniel Vetter wrote: > We chase pointers/lists without taking the locks protecting them, > which isn't that good. > > Fix it. > > v2: Actually unlock properly, spotted by Julia. The unlock is still on top of the unlock label? julia > > Cc: Julia Lawall <julia.lawall@lip6.fr> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> > --- > drivers/gpu/drm/drm_sysfs.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c > index 7506de0a75b4..9bffa63fe849 100644 > --- a/drivers/gpu/drm/drm_sysfs.c > +++ b/drivers/gpu/drm/drm_sysfs.c > @@ -261,23 +261,29 @@ static ssize_t edid_show(struct file *filp, struct kobject *kobj, > struct drm_connector *connector = to_drm_connector(connector_dev); > unsigned char *edid; > size_t size; > + ssize_t ret = 0; > > + mutex_lock(&connector->dev->mode_config.mutex); > if (!connector->edid_blob_ptr) > - return 0; > + goto unlock; > > edid = connector->edid_blob_ptr->data; > size = connector->edid_blob_ptr->length; > if (!edid) > - return 0; > + goto unlock; > > if (off >= size) > - return 0; > + goto unlock; > > if (off + count > size) > count = size - off; > memcpy(buf, edid + off, count); > > - return count; > + ret = count; > + mutex_unlock(&connector->dev->mode_config.mutex); > +unlock: > + > + return ret; > } > > static ssize_t modes_show(struct device *device, > @@ -288,10 +294,12 @@ static ssize_t modes_show(struct device *device, > struct drm_display_mode *mode; > int written = 0; > > + mutex_lock(&connector->dev->mode_config.mutex); > list_for_each_entry(mode, &connector->modes, head) { > written += snprintf(buf + written, PAGE_SIZE - written, "%s\n", > mode->name); > } > + mutex_unlock(&connector->dev->mode_config.mutex); > > return written; > } > -- > 2.5.1 > >
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c index 7506de0a75b4..9bffa63fe849 100644 --- a/drivers/gpu/drm/drm_sysfs.c +++ b/drivers/gpu/drm/drm_sysfs.c @@ -261,23 +261,29 @@ static ssize_t edid_show(struct file *filp, struct kobject *kobj, struct drm_connector *connector = to_drm_connector(connector_dev); unsigned char *edid; size_t size; + ssize_t ret = 0; + mutex_lock(&connector->dev->mode_config.mutex); if (!connector->edid_blob_ptr) - return 0; + goto unlock; edid = connector->edid_blob_ptr->data; size = connector->edid_blob_ptr->length; if (!edid) - return 0; + goto unlock; if (off >= size) - return 0; + goto unlock; if (off + count > size) count = size - off; memcpy(buf, edid + off, count); - return count; + ret = count; + mutex_unlock(&connector->dev->mode_config.mutex); +unlock: + + return ret; } static ssize_t modes_show(struct device *device, @@ -288,10 +294,12 @@ static ssize_t modes_show(struct device *device, struct drm_display_mode *mode; int written = 0; + mutex_lock(&connector->dev->mode_config.mutex); list_for_each_entry(mode, &connector->modes, head) { written += snprintf(buf + written, PAGE_SIZE - written, "%s\n", mode->name); } + mutex_unlock(&connector->dev->mode_config.mutex); return written; }
We chase pointers/lists without taking the locks protecting them, which isn't that good. Fix it. v2: Actually unlock properly, spotted by Julia. Cc: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> --- drivers/gpu/drm/drm_sysfs.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)