help !why cannot i get core file?

help !why cannot i get core file?

[wang]

hi all
   i use fedora 7.debug a device based on arm + linux using gdb on
fedora and gdbserver on device.
[root@wang wang]# ulimit -a
core file size          (blocks, -c) unlimited
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 2560
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 2560
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited
[root@wang wang]#

[root@wang wang]# /usr/local/arm-linux/bin/arm-linux-gdb -q
(gdb) file /home/wang/master/master.exe
Reading symbols from /home/wang/master/master.exe...done.
(gdb) target remote 192.168.1.203:2323
Remote debugging using 192.168.1.203:2323
Cannot access memory at address 0x0
0x40001b80 in ?? ()
(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
Cannot access memory at address 0x5a4
0x40046ca4 in ?? ()
---------------------------------------------------------
(gdb) q
The program is running.  Exit anyway? (y or n) y
[root@wang wang]# ls core.*
ls: cannot access core.*: No such file or directory
[root@wang wang]#

or
---------------------------------------------------------
(gdb) list core.*
Can't find member of namespace, class, struct, or union named "core.*"
Hint: try 'core.*<TAB> or 'core.*<ESC-?>
(Note leading single quote.)
(gdb)

but now  i didnot get a core file and i donot know witch line the
error occured at.
and what the "Cannot access memory at address 0x5a40x40046ca4 in ?? ()"  mean?

Re: help !why cannot i get core file?

[Jim Blandy]

wang <constant9824@gmail.com> writes:
> hi all
>    i use fedora 7.debug a device based on arm + linux using gdb on
> fedora and gdbserver on device.
> [root@wang wang]# ulimit -a
> core file size          (blocks, -c) unlimited
> data seg size           (kbytes, -d) unlimited
> scheduling priority             (-e) 0
> file size               (blocks, -f) unlimited
> pending signals                 (-i) 2560
> max locked memory       (kbytes, -l) 32
> max memory size         (kbytes, -m) unlimited
> open files                      (-n) 1024
> pipe size            (512 bytes, -p) 8
> POSIX message queues     (bytes, -q) 819200
> real-time priority              (-r) 0
> stack size              (kbytes, -s) 10240
> cpu time               (seconds, -t) unlimited
> max user processes              (-u) 2560
> virtual memory          (kbytes, -v) unlimited
> file locks                      (-x) unlimited

Unless I'm missing something, this ulimit command shows the limits
you've set on your host machine --- the machine running GDB --- and
not on the target machine --- the machine that's running the program
you want to debug.  You'll need to make sure that core dumps are
enabled in the kernel running on your target machine, and make sure
that ulimit -c is set appropriately *on that machine*.

> [root@wang wang]#
>
> [root@wang wang]# /usr/local/arm-linux/bin/arm-linux-gdb -q
> (gdb) file /home/wang/master/master.exe
> Reading symbols from /home/wang/master/master.exe...done.
> (gdb) target remote 192.168.1.203:2323
> Remote debugging using 192.168.1.203:2323
> Cannot access memory at address 0x0
> 0x40001b80 in ?? ()
> (gdb) c
> Continuing.
>
> Program received signal SIGSEGV, Segmentation fault.
> Cannot access memory at address 0x5a4
> 0x40046ca4 in ?? ()

This message means that GDB doesn't have debugging information for the
code at 0x40046ca4.  Are you running master.exe under gdbserver on the
target machine?  Did you compile master.exe with -g?