CVE-2021-47641

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> video: fbdev: cirrusfb: check pixclock to avoid divide by zero<br /> <br /> Do a sanity check on pixclock value to avoid divide by zero.<br /> <br /> If the pixclock value is zero, the cirrusfb driver will round up<br /> pixclock to get the derived frequency as close to maxclock as<br /> possible.<br /> <br /> Syzkaller reported a divide error in cirrusfb_check_pixclock.<br /> <br /> divide error: 0000 [#1] SMP KASAN PTI<br /> CPU: 0 PID: 14938 Comm: cirrusfb_test Not tainted 5.15.0-rc6 #1<br /> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2<br /> RIP: 0010:cirrusfb_check_var+0x6f1/0x1260<br /> <br /> Call Trace:<br /> fb_set_var+0x398/0xf90<br /> do_fb_ioctl+0x4b8/0x6f0<br /> fb_ioctl+0xeb/0x130<br /> __x64_sys_ioctl+0x19d/0x220<br /> do_syscall_64+0x3a/0x80<br /> entry_SYSCALL_64_after_hwframe+0x44/0xae