remote debugging: gdbserver backtrace on mips

[#-sadiq shaikh-# <saadiqshaikh at yahoo dot com>]

Hi,
 
Has anyone worked on gdbserver on mips platform, and
got thru the backtrace problem. when i do bt command
on the client(host) side i could see only innermost
frame, previous frames its trying to get but not
succeeding. Eventually giving error as 
--------------------------------------------------
(gdb) bt
#0? cal (a=0x803cff20, b=0x803cff24) at test.c:29
warning: Warning: GDB can't find the start of the
function at 0x803c82ec.
 
??? GDB is unable to find the start of the function at
0x803c82ec and thus can't determine the size of that
function's stack frame.This means that GDB may be
unable to access that stack frame, or the frames below
it.
??? This problem is most likely caused by an invalid
program counter or stack pointer. However, if you
think GDB should simply search farther back
from 0x803c82ec for code which looks like the
beginning of a function, you can increase the range of
the search using the `set heuristic-fence-post'
command.
(gdb)
--------------------------------------------------
 
#)Is it because of difference in addressing schemes on
both target/host.Does client expect addresses in some
format from the server.
#)My target is mips running uclinux flat binary.
#) Host is linux running mips-linux-gdb cross compiled
gdb client.
#) Server-client talk over ethernet via tcp.
#) In dump i could see that server is conveying client
the loaded address(text/data sections) of the
programme.
#) However on host while loading symbol file, i tried
manually giving sections address of the programme
running on the target, as well as without giving the
section addresses. Both method yielded no result.I
mean error persist !
#) I also tried setting heuristic-fence-post, but?
observe no good result.
#)gdb client already knows the finals address where
the programme is running on the target and offset in
the symbol file, but still its not able to find the
prev frames ?
#)what is that more gdb client expecting from the
server ?
#)I have seen register dump on the client and appears
to be fine, then what is stopping client from passing
thru the stack frames and displaying properly all
frames in the stack ?
 
Any help on these score will be helpfull.Thanking you
in anticipation.
 
Regards,
sadiq.shaikh
?


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