Re: Re: drivers/s390/char/keyboard.c NULL pointer reference

[Heiko Carstens]

On Sat, Aug 05, 2017 at 09:44:45AM +0800, sohu0106 wrote:
> 
> 
> I don't understand a bit,My idea is 
> 
> in userland
> 
> fd=open("tty3270",O_RDONLY)
> ...
> ret=ioctl(fd,KDGKBDIACR,NULL)
> ...
> 
> then here 
> drivers/s390/char/keyboard.c
> 477 
> case KDGKBDIACR:
> 	{
> 		struct kbdiacrs __user *a = argp;
> 		struct kbdiacr diacr;
> 		int i;
> 		
> 		//a is NULL,a->kb_cnt will crash
> 		if (put_user(kbd->accent_table_size, &a->kb_cnt))

a->kb_cnt and &a->kb_cnt is not the same...