----- Original Message -----
On 11/19/2015 08:37 AM, David Mair wrote:
> On 11/19/2015 07:45 AM, Dave Anderson wrote:
>
> Hi Dave,
>
>> ----- Original Message -----
> <snip>
>>
>>> (2) Execute "crash -d8" on physical machine will cause crash
utility core
>>> dump.
>>
>> I can reproduce this, so I'll look into it. It's related to the
/dev/mem
>> "test"
>> to determine whether the kernel was configured with CONFIG_STRICT_DEVMEM,
>> where
>> it tries to read from pfn 257 (just above the CONFIG_STRICT_DEVMEM limit),
>> but
>> gets into an infinite loop when used in conjunction with -d.
>>
>> Anyway, just continue to use /proc/kcore and you should be fine.
>
> This is the cause in readmem():
>
> switch(READMEM(...))
> {
> .
> .
> .
> case READ_ERROR:
> if (PRINT_ERROR_MESSAGE) ********** THIS ***********
> {
> causes a nested readmem() call before the goto gives it
> to the caller to deal with
> }
> goto readmem_error
> }
> .
> .
> .
> switch(error_handle)
> {
> case (RETURN_ON_ERROR):
> }
>
> The PRINT_ERROR_MESSAGE I assume is an escalation from -d 8 in this case.
>
The whole switch_to_proc_kcore() probably shouldn't be conditional on
the presence of PRINT_ERROR_MESSAGE, only the actual error message
should be.
Patch shortly.
Exactly -- I was just about to send out a long-winded explanation but saw
this response.
Thanks for debugging this!
Dave