Re: [Qemu-devel] The linux-based system runs perfectly on vmware, but kernel panic on qemu

[Mulyadi Santosa]

Hi..

On Jan 18, 2008 5:10 PM, Марк Коренберг <address@hidden> wrote:
> Thanks.
>
> I reproduced the same bugs with kqemu disabled on md5checking
> but without kqemu hwclock work correctly!
At least we got suspect: kqemu.

> very strange... why md5checking generates bug ?

I really don't have any idea. Maybe md5sum is doing many integer
computation/hashing, thus hitting floating point bug? Everybody, have
a clue? or maybe it's doing map/unmapping in large volume?

> I don't think that there is defference in RTC driver between qemu
> version. i'm always read changelogs.

Hm, ok.

> md5sum check - is running /usr/bin/md5sum with list of files. nothing
> special. just massive IO operations. bug appear after md5sums
> complete. just after "echo" in bash and before "read answer" command.
>
> if ! md5sums ... ; then
>  echo "(yes/no)?"
>  #bug appear here
>  read answer
>  if [ "$answer" != yes ]; then
>   .....
>
>
> At a time writing this message, i found, that ksyms or ksymoops should
> give huge help. But we use 2.4.24 kernel without modularity enabled
> (our system is embedded and modules functionality is not needed in the
> kernel). so i can't get ksyms and ksymoops to work.
> some manuals say me to use /dev/ksyms, some of them /proc/ksyms and
> also /proc/kallsyms. Maybe /proc/ksyms should be enabled in kernel
> anyhow ?
> where to read about ksyms and _simple_ debugging ?

Here is what I used to do:
Compile the kernel with -g flags. You can do it manually by adding -g
to CFLAGS in Makefile. I remember there is other variant of CFLAGS
there...just add it to all of them. Also, don't enable
optimization..simply throw out -O flag

it will create vmlinux filled with debugging symbol. use it with gdb
to find out the address of a function/variable.

is it helpful for you?

regards,

Mulyadi.