CVE-2022-49978 fbdev: fb_pm2fb: Avoid potential divide by zero error

In the Linux kernel, the following vulnerability has been resolved: fbdev: fbpm2fb: Avoid potential divide by zero error In dofbioctl of fbmem.c, if cmd is FBIOPUTVSCREENINFO, var will be copied from user, then go through fbsetvar and info-fbops-fbcheckvar which could may be pm2fbcheckvar. Along...