Hello Thomas,
On 5/2/22 15:20, Thomas Zimmermann wrote:
Am 02.05.22 um 15:09 schrieb Javier Martinez Canillas:
A reference to the framebuffer device struct fb_info is stored in the file private data, but this reference could no longer be valid and must not be accessed directly. Instead, the file_fb_info() accessor function must be used since it does sanity checking to make sure that the fb_info is valid.
This can happen for example if the fbdev driver was one that is using a framebuffer provided by the system firmware. In that case, the fbdev core could unregister the framebuffer device if a real video driver is probed.
Reported-by: Maxime Ripard maxime@cerno.tech Signed-off-by: Javier Martinez Canillas javierm@redhat.com
Reviewed-by: Thomas Zimmermann tzimmermann@suse.de
Thanks.
This seems like the correct thing to do in any case. Thanks for the
Agreed, it's certainly a bug if not the same that was already reported.
patch. Before merging, you should also add
Fixes: 27599aacbaef ("fbdev: Hot-unplug firmware fb devices on forced removal")
I thought about that but I don't think that's accurate since the bug is not related to that commit. That might make easier to reproduce it but is something that would happen anyway if for example someone attempted to remove a module or unbind the device using the sysfs entries.
Maybe I can comment in the commit message that this change made it more likely to occur and for that reason I'm adding a fixes tag.
Reported-by: Junxiao Chang junxiao.chang@intel.com
Indeed. -- Best regards,
Javier Martinez Canillas Linux Engineering Red Hat