Drivers are supposed to fix this up if needed if they don't outright reject it. Uncovered by 6c11df58fd1a ("fbmem: Check virtual screen sizes in fb_set_var()").

Reported-by: syzbot+20dcf81733d43ddff661@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=c5faf983bfa4a607de530cd3bb008888bf06cef... Cc: stable@vger.kernel.org # v5.4+ Cc: Daniel Vetter daniel@ffwll.ch Cc: Javier Martinez Canillas javierm@redhat.com Cc: Thomas Zimmermann tzimmermann@suse.de Signed-off-by: Daniel Vetter daniel.vetter@intel.com --- drivers/gpu/drm/drm_fb_helper.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 59409820f424..eb4ece3e0027 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1595,6 +1595,9 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var, return -EINVAL; }

+ var->xres_virtual = fb->width; + var->yres_virtual = fb->height; + /* * Workaround for SDL 1.2, which is known to be setting all pixel format * fields values to zero in some cases. We treat this situation as a