tree 7bc4ca2a1a6e01f825165d585d9ce37b87419f36
parent f2bfd792c1ed4b1e0578db3fcdb0879dc87fe027
author Zheyu Ma <zheyuma97@gmail.com> 1649062041 +0800
committer Helge Deller <deller@gmx.de> 1649658230 +0200

video: fbdev: tridentfb: Error out if 'pixclock' equals zero

The userspace program could pass any values to the driver through
ioctl() interface. If the driver doesn't check the value of 'pixclock',
it may cause divide error.

Fix this by checking whether 'pixclock' is zero.

The following log reveals it:
 divide error: 0000 [#1] PREEMPT SMP KASAN PTI
 RIP: 0010:tridentfb_check_var+0x853/0xe60
 Call Trace:
  <TASK>
  fb_set_var+0x367/0xeb0
  do_fb_ioctl+0x234/0x670
  fb_ioctl+0xdd/0x130
  do_syscall_64+0x3b/0x90

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>