drm: Fix memory leak at error path of drm_read()

tiwai · danvet · commit a0a0bde32a46 · 2014-12-04T13:28:42.000+01:00
Note that the read manpages explicitly states that the read position
is undefined on error. Since EFAULT is just a userspace bug we are
therefore fine with just dropping the event on the floor.

Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
[danvet: Add note that just dropping the event is ok.]
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
@@ -527,6 +527,7 @@ ssize_t drm_read(struct file *filp, char __user *buffer,
 		if (copy_to_user(buffer + total,
 				 e->event, e->event->length)) {
 			total = -EFAULT;
+			e->destroy(e);
 			break;
 		}
 

Original file line number	Diff line number	Diff line change
`@@ -527,6 +527,7 @@ ssize_t drm_read(struct file filp, char __user buffer,`
`527`	`527`	`if (copy_to_user(buffer + total,`
`528`	`528`	`e->event, e->event->length)) {`
`529`	`529`	`total = -EFAULT;`
	`530`	`+ e->destroy(e);`
`530`	`531`	`break;`
`531`	`532`	`}`
`532`	`533`