Re: Fix solib-disc.exp regression with x86 gdbserver

[Pedro Alves <pedro@codesourcery.com>]

On Sunday 11 April 2010 15:04:39, H.J. Lu wrote:
> How can I debug gdbserver with gdb? I tried and it didn't work.

What doesn't work?  It Just Works for me:

 $gdb -q --args ./gdbserver :9999 ~/gdb/tests/threads
 Reading symbols from /home/pedro/gdb/gdbserver_tracepoints_step_over_bkpt_pushed/build/gdb/gdbserver/gdbserver...done.
 (gdb) start
 Temporary breakpoint 1 at 0x40f51f: file ../../../src/gdb/gdbserver/server.c, line 2238.
 Starting program: /home/pedro/gdb/gdbserver_tracepoints_step_over_bkpt_pushed/build/gdb/gdbserver/gdbserver :9999 /home/pedro/gdb/tests/threads
 
 Temporary breakpoint 1, main (argc=4, argv=0x7fffffffe068) at ../../../src/gdb/gdbserver/server.c:2238
 2238      char **next_arg = &argv[1];
 (gdb)


Attaching works too:

 $ ./gdbserver :9999 ~/gdb/tests/threads
 ...

 $ gdb -p $(pidof gdbserver)
 ...

It used to be GDB would get confused due to the uses of the clone
syscall in linux-low.c, and so breakpoints wouldn't work.  The
easy workaround was just to comment out the linux_test_for_tracefork
call (and hardcode linux_supports_tracefork_flag as 1, to get the
same behaviour you'd get without the hack).  clone is only used
on uclinux/nommu, so you shouldn't need the hack anymore on linux.

gdbserver's "--debug" command line switch is also useful (it enables
all that the internal debug output controlled by `if (debug_threads)').
"(gdb) monitor set debug 1" has the same effect.

-- 
Pedro Alves