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RE: Q: GDB - Threads
I'm here again...
Tried all suggestions... but still not working.
I guess I'm missing something but ..... What?
Some ideas or hints, or some places ..where to find more info ?
I've been digging in the GDB-manual and mailing list for some time
now... :-( :-(
I'll try to give a small resume of what I'm trying to do.
*HOST : PC (ubuntu 9.04)
*TARGET : ARM (at91sam9g20)
*Buildsystem: buildroot 06/2009 - uclibc-0.9.30.1, gdb 6.8,gcc-4.3.3
*Striping : TURNED OFF. (for all files, this also means libs)
*Test-Application : a simpe applciation that uses PTHREAD's!!
*GDB: GDB / Gdbserver 6.8 for ARM (all is built for arm-linux-uclibc- )
When the application is run in 'remote-'gdb the application 'HANGS' as
soon as the second thread is created.
(target : gdbserver *:9000 ./threading)
(host : gdb - over TCP/IP -> target ip-address port 9000)
>>> target console log <<<
# gdbserver *:9000 ./threading
Process ./threading created; pid = 905
Listening on port 9000
Remote debugging from host 150.158.205.4
Creating thread 0
0: Hello World! 0
Creating thread 1
0: Hello World! 1
--->> and now .. the target is 'HANGING' <<---------
>> a normal run on the target ARM -- gives me the expected output <<
When the Test-application runs STAND-ALONE on the target (normal
behavoir... As expected ;-))
./threading
Creating thread 0
0: Hello World! 0
Creating thread 1
1: Hello World! 0
Creating thread 2
2: Hello World! 0
Creating thread 3
3: Hello World! 0
Creating thread 4
4: Hello World! 0
Sleeping/printing in main .....
printing in main 0
0: Hello World! 1
1: Hello World! 1
2: Hello World! 1
<< some things.. Are removed here >>
Hello World! 19
4: Hello World! 19
printing in main 19
printing in main 20
printing in main 21
printing in main 22
printing in main 23
printing in main 24
printing in main 25
printing in main 26
printing in main 27
printing in main 28
printing in main 29
Sleeping in main ..... DONE ..
What I do not understand is the following:
Most people (that have responded, again THANKS for all responses, and
sorry I'll keep on bothering you all, but I'm just trying to get my
DEBUGGING problem solved..) point me to the fact that my libs
(especially libthread_db) would be a wrong version..
But here it comes ... I can't see/understand why I would need
libthread_db .. I'm using pthreads !
In fact the only thing I try (at this time) is to step in the 'main' of
the program, even not in a 'p'thread.
<< please have a look at this GDB-CONSOLE-LOG >>
/buildhome/20090601/buildroot/toolchain_build_arm/gdbhost-6.8/gdb$ ./gdb
GNU gdb 6.8
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show
copying"
and "show warranty" for details.
This GDB was configured as "--host=i386-pc-linux-gnu
--target=arm-linux-uclibc".
Setting up the environment for debugging gdb.
Setting up the environment for debugging gdb - DONE .
Breakpoint 1 at 0x8784: file sources/main.c, line 46.
(NOEL2-gdb) run
Starting program: /tmp/threading
[New Thread 906]
[Switching to Thread 906]
Stopped due to shared library event
(NOEL2-gdb) c
Continuing.
Stopped due to shared library event
(NOEL2-gdb) info shared li
From To Syms Read Shared Object Library
0x40000930 0x40003eb0 Yes
/buildhome/20090601/buildroot/project_build_arm/at91sam9g20ek/root/lib/l
d-uClibc.so.0
0x40011cc0 0x4001820c Yes
/buildhome/20090601/buildroot/project_build_arm/at91sam9g20ek/root/lib/l
ibpthread.so.0
0x40029ca0 0x40030ec4 Yes
/buildhome/20090601/buildroot/project_build_arm/at91sam9g20ek/root/lib/l
ibgcc_s.so.1
0x40044c90 0x400855b0 Yes
/buildhome/20090601/buildroot/project_build_arm/at91sam9g20ek/root/lib/l
ibc.so.0
(NOEL2-gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x00008784 in main at sources/main.c:46
(NOEL2-gdb) l
37 }
38 pthread_exit(NULL);
39 }
40
41 int main()
42 {
43 pthread_t threads[NUM_THREADS];
44 int rc, t;
45 for(t=0;t<NUM_THREADS;t++){
46 printf("Creating thread %d\r\n", t);
(NOEL2-gdb) l
47 rc = pthread_create(&threads[t], NULL, PrintHello, (void
*)t);
48 if (rc){
49 printf("ERROR; return code from pthread_create() is
%d\r\n", rc);
50 exit(-1);
51 }
52 }
53
54 printf("Sleeping/printing in main ..... \r\n");
55 {
56 int n;
(NOEL2-gdb) b main.c:48
Breakpoint 2 at 0x87f8: file sources/main.c, line 48.
(NOEL2-gdb) c
Continuing.
Breakpoint 1, main () at sources/main.c:46
46 printf("Creating thread %d\r\n", t);
(NOEL2-gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x00008784 in main at sources/main.c:46
breakpoint already hit 1 time
2 breakpoint keep y 0x000087f8 in main at sources/main.c:48
(NOEL2-gdb) info shared li
From To Syms Read Shared Object Library
0x40000930 0x40003eb0 Yes
/buildhome/20090601/buildroot/project_build_arm/at91sam9g20ek/root/lib/l
d-uClibc.so.0
0x40011cc0 0x4001820c Yes
/buildhome/20090601/buildroot/project_build_arm/at91sam9g20ek/root/lib/l
ibpthread.so.0
0x40029ca0 0x40030ec4 Yes
/buildhome/20090601/buildroot/project_build_arm/at91sam9g20ek/root/lib/l
ibgcc_s.so.1
0x40044c90 0x400855b0 Yes
/buildhome/20090601/buildroot/project_build_arm/at91sam9g20ek/root/lib/l
ibc.so.0
(NOEL2-gdb) c
Continuing.
Breakpoint 2, main () at sources/main.c:48
48 if (rc){
(NOEL2-gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x00008784 in main at sources/main.c:46
breakpoint already hit 1 time
2 breakpoint keep y 0x000087f8 in main at sources/main.c:48
breakpoint already hit 1 time
(NOEL2-gdb) c
Continuing.
<< HANGING >>
I would expect the GDB-debugger to stop at main.c:48 (the break point is
still there ...) but it doesn't. (and the programs HANGS forever)!
The Target Console output I get is :
Remote debugging from host 150.158.205.4
Process /tmp/threading created; pid = 906
Creating thread 0
0: Hello World! 0
Creating thread 1
0: Hello World! 1
<< HANGING >>
Kind regards,
Noel.
-----Original Message-----
From: Daniel Jacobowitz [mailto:drow@false.org]
Sent: 2Jun09 21:34
To: Paul Pluzhnikov
Cc: Vellemans, Noel; gdb@sourceware.org
Subject: Re: Q: GDB - Threads
On Tue, Jun 02, 2009 at 11:34:40AM -0700, Paul Pluzhnikov wrote:
> On Tue, Jun 2, 2009 at 11:17 AM, Daniel Jacobowitz <drow@false.org>
wrote:
>
> > GDB never uses libthread_db on the host if it is debugging a remote
> > target.
>
> Oops. Sorry, my mistake.
>
> I guess then OP needs to verify that GDB is loading symbols from
> expected libpthread ("set verbose on" should show that), and that
> gdbserver on target is loading expected libthread_db ("ldd gdbserver"
> on target should show that).
Right. I don't remember if gdbserver's debug output helps with this or
not.
--
Daniel Jacobowitz
CodeSourcery