gdb出错：Can't attach LWP 3001: No such process

ksappsvr程序是fork出来的子进程，其中有多个线程，但是启动gdb调试就出现core dump,并且core dump的位置就是我设置断点的位置，希望高手指点

[test@CLINUX testqhsrv]$ gdb ksappsvr
GNU gdb Red Hat Linux (5.3post-0.20021129.18rh)
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This GDB was configured as "i386-redhat-linux-gnu"...
(gdb) attach 3003
Attaching to program: /home/test/testqhsrv/ksappsvr, process 3003
Reading symbols from /usr/lib/libstdc++.so.5...done.
Loaded symbols for /usr/lib/libstdc++.so.5
Reading symbols from /lib/tls/libpthread.so.0...done.
[New Thread 1074882848 (LWP 3001)]
Error while reading shared library symbols:
Can't attach LWP 3001: No such process
Reading symbols from /lib/tls/libm.so.6...done.
Loaded symbols for /lib/tls/libm.so.6
Reading symbols from /lib/libgcc_s.so.1...done.
Loaded symbols for /lib/libgcc_s.so.1
Reading symbols from /lib/tls/libc.so.6...done.
Loaded symbols for /lib/tls/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
0xffffe002 in ?? ()
(gdb) b pushthread.cpp:156
Breakpoint 1 at 0x806520f: file pushthread.cpp, line 156.
(gdb) c
Continuing.
Segmentation fault