[RFC] dev/mem: "memtester -p 0x6c80000000000 10G" cause crash

[Xishi Qiu]

Hi, I use "memtester -p 0x6c80000000000 10G" to test physical address 0x6c80000000000
Because this physical address is invalid, and valid_mmap_phys_addr_range()
always return 1, so it causes crash.

My question is that should the user assure the physical address is valid?

...
[ 169.147578] ? panic+0x1f1/0x239
[ 169.150789] oops_end+0xb8/0xd0
[ 169.153910] pgtable_bad+0x8a/0x95
[ 169.157294] __do_page_fault+0x3aa/0x4a0
[ 169.161194] do_page_fault+0x30/0x80
[ 169.164750] ? do_syscall_64+0x175/0x180
[ 169.168649] page_fault+0x28/0x30

Thanks,
Xishi Qiu