On Tue, May 03, 2022 at 10:19:34PM +0200, Javier Martinez Canillas wrote:
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 registered framebuffer device is for a driver that just uses a framebuffer provided by the system firmware. In that case, the fbdev core would unregister the framebuffer device when a real video driver is probed and ask to remove conflicting framebuffers.
Most fbdev file operations already use the helper to get the fb_info but get_fb_unmapped_area() and fb_deferred_io_fsync() don't. Fix those two.
Since fb_deferred_io_fsync() is not in fbmem.o, the helper has to be exported. Rename it and add a fb_ prefix to denote that is public now.
Reported-by: Junxiao Chang junxiao.chang@intel.com Signed-off-by: Javier Martinez Canillas javierm@redhat.com
Acked-by: Sam Ravnborg sam@ravnborg.org