On Wed May 18 2011 about 10:37:54 EST, Stevie Trujillo wrote:
> I'm having some problem getting a backtrace. When I do "modprobe -r
> iwlagn; modprobe iwlagn" (2.6.38.6 with Intel-1030N) the kernel crashes
> (sometimes I need to try 2 or 3 times, and sometimes the modprobe -r
> is the one that crashes).
>
> This spams my monitor with several oops/panics before it finally
> dies. I can only see bottom of the last one, which probably isn't
> very meaningful. I tried loading netconsole, but I only get one or
> two lines before it stops sending/printing.
>
> I then tried kexec+crashkernel, but I only managed to get a backtrace
> for the last panic (which I think is just a result of memory corruption
> or something). Finally I tried compiling ramoops into my kernel,
> but it didn't want to load because of "No such device".
For the kexec+crashkernel, try to retrieve the kernel log buffer:
There are some macros available, but basically log_buf is a pointer
to a buffer of length log_buf_len initialized to __log_buf (but can
be expanded via the command line or sysctl, in). log_end is the
end of the buffer. If you haven't wrapped then just print log_end
characters.
Also consider setting /proc/sys/kernel/panic_on_oops to 1 to
concentrate on the first one. It won't help getting the oops to your
syslog but maybe it will keep it on the screen.
Hope this helps,
milton
On Wed, May 18, 2011 at 11:55 PM, Milton Miller <[email protected]> wrote:
> On Wed May 18 2011 about 10:37:54 EST, Stevie Trujillo wrote:
>> I'm having some problem getting a backtrace. When I do "modprobe -r
>> iwlagn; modprobe iwlagn" (2.6.38.6 with Intel-1030N) the kernel crashes
>> (sometimes I need to try 2 or 3 times, and sometimes the modprobe -r
>> is the one that crashes).
>>
>> This spams my monitor with several oops/panics before it finally
>> dies. I can only see bottom of the last one, which probably isn't
>> very meaningful. I tried loading netconsole, but I only get one or
>> two lines before it stops sending/printing.
>>
>> I then tried kexec+crashkernel, but I only managed to get a backtrace
>> for the last panic (which I think is just a result of memory corruption
>> or something). Finally I tried compiling ramoops into my kernel,
>> but it didn't want to load because of "No such device".
>
> For the kexec+crashkernel, try to retrieve the kernel log buffer:
>
There is a utility in kexec-tools, named vmcore-dmesg, which
is supposed to do this kind of thing.