[GDB] Connecting Insight makes the program crashes

[shazz]

Hello,

I tried to debug a very simple program using :
- latest svn KOS
- dcload serial 1.0.4
- sh-elf-gdb 6.8
- sh-elf_insight (compiled for sh-elf) 6.8.1

when I tried insight connects to the loaded application, it crashes everytime :

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opt/toolchains/dc/sh-elf/bin/sh-elf-gcc -O2 -fomit-frame-pointer -ml -m4-single-only -fno-crossjumping -I/opt/toolchains/dc/kos/../kos-ports/include -I/opt/toolchains/dc/kos/include -I/opt/toolchains/dc/kos/kernel/arch/dreamcast/include -I/opt/toolchains/dc/kos/addons/include -D_arch_dreamcast -D_arch_sub_pristine -Wall -g -fno-builtin -fno-strict-aliasing  -ml -m4-single-only -Wl,-Ttext=0x8c010000 -nostartfiles -nostdlib -L/opt/toolchains/dc/kos/lib/dreamcast -L/opt/toolchains/dc/kos/addons/lib/dreamcast -o gdbtest.elf /opt/toolchains/dc/kos/kernel/arch/dreamcast/kernel/startup.o \
		gdbtest.o  -Wl,--start-group -lkallisti -lc -lgcc -Wl,--end-group

dc-tool -g -x gdbtest.elf

Starting a GDB server on port 2159
Console enabled
Upload <gdbtest.elf>
[...]
KallistiOS ##version##: Fri Feb 19 16:38:13 CET 2010
[...]
thd: pre-emption enabled, HZ=100
[...]
dc-load console support enabled
[...]
waiting for gdb client connection...

I run insight, connect to GDBserver/Serial / Baud Rate: same baudrate used for dc-tool / remote target: 2159
it tries to connect, says successful then... crash

Code: Select all

Unimplemented command (110) 
Assuming program has exited, or something...

Any idea ?

the code :

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#include <kos.h>
#include <arch/gdb.h>

int main(int argc, char **argv)
{
   gdb_init();
   
   int val = 12;
   printf("\nHello world from gdb ! %d\n\n", val);
   return 0;
} 

[Quzar]

I'll look into it more later if nobody else has given you a better answer, but I *think* you also have to recompile your libs (kos) as '-g' in order for it to work right... I might be way off base though

[emptythought]

Try KOS' debug "logging" method.

Add this to your includes:

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#include "kos/dbglog.h"

Use this instead of printf:

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dbglog(DBG_DEBUG, "");

So try running this in GDB\Insight:

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/* #include <string.h> */

#include "arch/gdb.h"
#include "kos/dbglog.h"

int main(int argc, char **argv)
{
   gdb_init();
   
   printf("Hello world from gdb!\n");
   return 0;
}

[shazz]

emptythought, I tried.. not really better. (or a little, dc-tool still exits but without the 'Unimplemented command (110)
Assuming program has exited, or something..." message)

insight says "successfully connected", the dc-tool shell exit, but when I click on the Run button, nothing happens and if I open the gdb shell I can see :

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0x8c0120c4 in gdb_init () at gdb_stub.c:988
Remote communication error: Connection reset by peer.

(gdb) 
Error: putpkt: write failed: Broken pipe.

gdb_stub.c:988 :

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#define BREAKPOINT()   asm("trapa	#0xff"::);
BREAKPOINT()

Which version of gdb+insight are you using ? as all versions prior to 6.8 are broken due to a tcl/tk bug with ubuntu (or any debian distrib it seems) I cannot try another one...

[shazz]

I tried a second time with my new 4.4.0 gcc toolchain.... exactly the same behavior.
So or the feature is broken, or there is a dedicated gdb version to use... or I'm not lucky !

[Quzar]

Have you checked that you have the newest version of dcload/tool? Support for gdb was only (relatively) recently made stable.

[shazz]

Unless the "latest" dcload version is not in the svn... yes I have checked. To be sure I have burnt a new CD.... same result.

[Quzar]

Hrm. Have you tried connecting without insight? Using plain cli gdb? That would at least eliminate one component.

[shazz]

I'll try (I tried thru the insight gdb shell but not directly)
Do you know the exact commands to pass ? (for serial /dev/ttyS0, 115200 bps)

[emptythought]

Do you have Newlib 1.15? If you do try Newlib 1.12, 1.15 has some issues with printf that need to be fixed.

[BlueCrab]

Do you have Newlib 1.15? If you do try Newlib 1.12, 1.15 has some issues with printf that need to be fixed.

I've never had a single issue with Newlib 1.15.0 myself. Also, as of r657 of KOS in the Subversion, Newlib 1.15.0 is required.

[emptythought]

There's an old post on the mailing list about it, it basically says that Newlib 1.15 and printf on DC does not work. That's why I suggested the debugger log.

[shazz]

Yes I'm using Newlib 1.15.. I'll try 1.12 in case of.

Nevertheless, as I've got a BBA now, I tried the ip version... even worse ! Using the same test application (see code above), dc-tool 1.0.4 doesn't display anymore the "waiting for gdb client connection", it starts to execute the code as without the -g arg then freezes...

damn... is there anybody here who really uses gdb/insight ????