[Crash-utility] dis command not correct in crash

[Per Fransson]

Hi Lei,

On Tue, Mar 5, 2013 at 1:22 AM, Lei Wen <adrian.wenl at gmail.com> wrote:
> Hi Per,
>
>
> On Tue, Mar 5, 2013 at 4:38 AM, Per Fransson <per.fransson.ml at gmail.com>
> wrote:
>>
>> Hi,
>>
>> On Mon, Mar 4, 2013 at 8:49 PM, Mika Westerberg <mika.westerberg at iki.fi>
>> wrote:
>> > On Mon, Mar 04, 2013 at 10:20:42AM +0800, Lei Wen wrote:
>> >> I met "dis" command not correct issue when use the crash, any idea?
>> >> For built-in "dis" command in crash:
>> >> crash> dis task_rq_lock
>> >> 0xc015a2d8 <task_rq_lock>:      rscsgt  r0, sp, r3, lsl #14
>> >> 0xc015a2dc <task_rq_lock+4>:    mrcgt   8, 7, r0, cr2, cr13, {5}
>> >> 0xc015a2e0 <task_rq_lock+8>:    mcrvc   8, 4, r3, cr13, cr3, {6}
>> >> 0xc015a2e4 <task_rq_lock+12>:   lslsvc  r3, r10, r8
>> >> 0xc015a2e8 <task_rq_lock+16>:   bl      0xc049fe34
>> >> <__ip_route_output_key+220>
>> >
>> > Looks weird.
>> >
>> > What is the kernel version? Does the 'dis' command work for other
>> > functions?
>> >
>>
>> You could do a check on one of the instructions - the 'bl' comes to
>> mind. Not sure, but I believe it should amount to:
>>
>> 0xeb000000 | (((0xc049fe34-0xc015a2f0) >> 2) & 0x00ffffff)
>>
>> i.e.
>>
>> 0xeb0d16d1
>>
>> Is that what you get with
>>
>> crash> rd 0xc015a2e8
>>
>> ?
>>
>> If not, try a
>>
>> crash> search 0xeb0d16d1
>>
>> and see if it turns up somewhere else.
>
>
>
>
> Yes, it is that value.
>
> crash> rd 0xc015a2e8
>
> c015a2e8:  eb0d16d1                              ....
>
>
>
> While in gdb, show the same address's value, it would be:
>
> (gdb) x 0xc015a2e8
>
> 0xc015a2e8 <task_rq_lock+16>:   0xe1a05000
>
>
>
> Why it didn't match with each other? Any idea?
>
>

Nope, no idea. When you're using gdb, do you feed it the coredump as
well, or just the vmlinux? if you get the same strange result with
gdb+vmlinux+coredump, I think you should try to match some known data,
e.g. the 'bl' and see if the contents are offset somehow. Try the gdb
search command on 0xeb0d16d1.

I accidently answered directly to you first Lei, but please respond
here on the list.

/Per

>
> Thanks,
>
> Lei