Identifying structures related to memory , semaphores using crash utility

Hi all,I was running crash to analyse a vmcore generated by a  2.6.16.21-0.8.uis.1-smp kernel ( on x86_64 architecture). During this I came to know that we get a list of all kernel symbols with the help of "sym -l" command. With the help of "whatis" command we can know the symbol definition.But applying "whatis" command to each symbol and checking its definition appears to be tedious. Is there any other way to identify as to which symbols represent structures?        Also I wanted to isolate the structures related to memory, semaphores, tasks. Since I am new to crash utility, I couldn't get much information. Could you please provide some suggestions as to how to go about it.Thanks,Ramya

---

Need a quick answer? Get one in minutes from people who know. Ask your question on Yahoo! Answers.

Ask "Yahoo! Answers"?   

Anyway, it's not clear to me what you're asking for?

If a symbol-name is an instance of a data structure, or an array of data
structures, you can simply enter:

  crash> p symbol-name

If the symbol refers to an array of structures, you can pick
an individual structure by its index:

  crash> p symbol-name[index]

Or if the symbol is a pointer to a data strucutre, you display
what it points to with:

  crash> p *symbol-name

The above simply take advantage of the embedded gdb module
pre-determining what the data type of a symbol is, and then printing it.

When you ask that you want to "isolate the structures related to
memory, semaphores, tasks", again, I don't understand what you
are asking for.

I'm probably missing your point, but, in any case, there's certainly no
existing command that walks the symbol list and tells you what kind of
data structure each one is -- if that's what you're expecting.

Depending upon what you want, you could probably (1) cobble together
an input script that you can in turn feed to crash, or (2) write an "extend"
module that gathers the data that you specifically need.

Dave
 
 

Ramya

Dave Anderson <andersonredhat.com> wrote:

ram ba wrote:

Hi all,I was running crash to analyse a vmcore generated by a  2.6.16.21-0.8.uis.1-smp kernel ( on x86_64 architecture). During this I came to know that we get a list of all kernel symbols with the help of "sym -l" command. With the help of "whatis" command we can know the symbol definition.But applying "whatis" command to each symbol and checking its definition appears to be tedious. Is there any other way to identify as to which symbols represent structures? &nbsp; &nbsp; &nbsp;  Also I wanted to isolate the structures related to memory, semaphores, tasks. Since I am new to crash utility, I couldn't get much information. Could you please provide some suggestions as to how to go about it.Thanks,Ramya

---

Need a quick answer? Get one in minutes from people who know. Ask your question on Yahoo! Answers.

Ask "Yahoo! Answers"?&nbsp;  

Anyway, it's not clear to me what you're asking for?

If a symbol-name is an instance of a data structure, or an array of data
structures, you can simply enter:

  crash> p symbol-name

If the symbol refers to an array of structures, you can pick
an individual structure by its index:

  crash> p symbol-name[index]

Or if the symbol is a pointer to a data strucutre, you display
what it points to with:

  crash> p *symbol-name

The above simply take advantage of the embedded gdb module
pre-determining what the data type of a symbol is, and then printing it.

When you ask that you want to "isolate the structures related to
memory, semaphores, tasks", again, I don't understand what you
are asking for.

I'm probably missing your point, but, in any case, there's certainly no
existing command that walks the symbol list and tells you what kind of
data structure each one is -- if that's what you're expecting.

Depending upon what you want, you could probably (1) cobble together
an input script that you can in turn feed to crash, or (2) write an "extend"
module that gathers the data that you specifically need.

Dave
 
  --
Crash-utility mailing list
Crash-utilityredhat.com
https://www.redhat.com/mailman/listinfo/crash-utility

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com

Ramya
Rachita Kothiyal <rachitain.ibm.com> wrote:

On Mon, Dec 11, 2006 at 08:19:32PM -0800, ram ba wrote:
>; Hi Dave,
> I am thankful to you for your immediate response. Since we know that symbols can be either structures, arrays, ordinary variables or functions, I want to fetch the values of only those symbols that are structures. Well when we execute sym -l command, we get the second field as symbol type as shown below.
>;
> ffffffff80107000 (T) level3_physmem_pgt
&gt; ffffffff80108000 (t) rest_init
> .....
> ffffffff80333000 (D) cpu_gdt_table
> ffffffff80333080 (d) gdt_end
&gt; .....
> ffffffff802d93a0 (A) __stop___ex_table
>; ffffffff802da000 (A) __start_rodata
> ffffffff802da000 (R) linux_banner
> ffffffff802da0c0 (r) p.13105
&gt; ffffffff802da100 (r) border
>;
> I wanted to ensure whether we can use this information to identify whether a given symbol is a structure or a function or an ordinary variable.( can i assume that all symbols present in text segment are functions?)

Hi Ramya

I dont see how one could determine whether a symbol is a structure or not
just by looking at the sym -l output. This is the same information one can
get from the System.map file. Probably one way could be to query 'gdb' for
each of these symbols for their symbol type, as Dave had mentioned.

Thanks
Rachita

--
Crash-utility mailing list
Crash-utilityredhat.com
https://www.redhat.com/mailman/listinfo/crash-utility