From: Daniel Vetter <daniel.vetter@xxxxxxxx>
Most fbdev drivers have issues with the fb_info lifetime, because call to
framebuffer_release() from their driver's .remove callback, rather than
doing from fbops.fb_destroy callback.
Doing that will destroy the fb_info too early, while references to it may
still exist, leading to a use-after-free error.
To prevent this, check the fb_info reference counter when attempting to
kfree the data structure in framebuffer_release(). That will leak it but
at least will prevent the mentioned error.
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---
drivers/video/fbdev/core/fbsysfs.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c
index 26892940c213..82e31a2d845e 100644
--- a/drivers/video/fbdev/core/fbsysfs.c
+++ b/drivers/video/fbdev/core/fbsysfs.c
@@ -80,6 +80,10 @@ void framebuffer_release(struct fb_info *info)
{
if (!info)
return;
+
+ if (WARN_ON(refcount_read(&info->count)))
+ return;
+
kfree(info->apertures);
kfree(info);
}
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