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

[Michal Hocko]

On Tue 02-05-17 15:59:23, Xishi Qiu wrote:
> 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?

We already seem to be checking range_is_allowed(). What is your
CONFIG_STRICT_DEVMEM setting? The code seems to be rather confusing but
my assumption is that you better know what you are doing when mapping
this file.

> ...
> [ 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

-- 
Michal Hocko
SUSE Labs