Linux 试图设置断点时，gdb无法访问附加进程中的内存

我正在调试postgres进程的用户定义函数（在自定义创建的libafd.so中找到）

在psql（运行postgres进程）中，获取进程的pid：

SELECT pg_backend_pid();
pg_backend_pid 
----------------
      22648
(1 row)

将gdb附加到进程（以根用户身份运行）：

加载一组符号时，有些符号失败：

GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04
Copyright (C) 2012 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 "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://bugs.launchpad.net/gdb-linaro/>...
Reading symbols from /usr/lib/postgresql/9.1/lib/libafd.so...done.
Attaching to program: /usr/lib/postgresql/9.1/lib/libafd.so, process 22648
Reading symbols from /usr/lib/x86_64-linux-gnu/libxml2.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libxml2.so.2
Reading symbols from /lib/x86_64-linux-gnu/libpam.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libpam.so.0
Reading symbols from /lib/x86_64-linux-gnu/libssl.so.1.0.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libssl.so.1.0.0
Reading symbols from /lib/x86_64-linux-gnu/libcrypto.so.1.0.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libcrypto.so.1.0.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libkrb5.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libkrb5.so.3
Reading symbols from /lib/x86_64-linux-gnu/libcom_err.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libcom_err.so.2
Reading symbols from /usr/lib/x86_64-linux-gnu/libgssapi_krb5.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libgssapi_krb5.so.2
Reading symbols from /lib/x86_64-linux-gnu/libdl.so.2...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libdl-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libdl.so.2
Reading symbols from /lib/x86_64-linux-gnu/libm.so.6...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libm-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libm.so.6
Reading symbols from /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libldap_r-2.4.so.2
Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libc-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libc.so.6
Reading symbols from /lib/x86_64-linux-gnu/libz.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libz.so.1
Reading symbols from /usr/lib/x86_64-linux-gnu/liblzma.so.5...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/liblzma.so.5
Reading symbols from /usr/lib/x86_64-linux-gnu/libk5crypto.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libk5crypto.so.3
Reading symbols from /usr/lib/x86_64-linux-gnu/libkrb5support.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libkrb5support.so.0
Reading symbols from /lib/x86_64-linux-gnu/libkeyutils.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libkeyutils.so.1
Reading symbols from /lib/x86_64-linux-gnu/libresolv.so.2...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libresolv-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libresolv.so.2
Reading symbols from /lib/x86_64-linux-gnu/libpthread.so.0...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libpthread-2.15.so...done.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
done.
Loaded symbols for /lib/x86_64-linux-gnu/libpthread.so.0
Reading symbols from /lib64/ld-linux-x86-64.so.2...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/ld-2.15.so...done.
done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /usr/lib/x86_64-linux-gnu/liblber-2.4.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/liblber-2.4.so.2
Reading symbols from /usr/lib/x86_64-linux-gnu/libsasl2.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libsasl2.so.2
Reading symbols from /usr/lib/x86_64-linux-gnu/libgssapi.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libgssapi.so.3
Reading symbols from /usr/lib/x86_64-linux-gnu/libgnutls.so.26...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libgnutls.so.26
Reading symbols from /lib/x86_64-linux-gnu/libgcrypt.so.11...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libgcrypt.so.11
Reading symbols from /usr/lib/x86_64-linux-gnu/libheimntlm.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libheimntlm.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libkrb5.so.26...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libkrb5.so.26
Reading symbols from /usr/lib/x86_64-linux-gnu/libasn1.so.8...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libasn1.so.8
Reading symbols from /usr/lib/x86_64-linux-gnu/libhcrypto.so.4...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libhcrypto.so.4
Reading symbols from /usr/lib/x86_64-linux-gnu/libroken.so.18...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libroken.so.18
Reading symbols from /usr/lib/x86_64-linux-gnu/libtasn1.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libtasn1.so.3
Reading symbols from /usr/lib/x86_64-linux-gnu/libp11-kit.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libp11-kit.so.0
Reading symbols from /lib/x86_64-linux-gnu/libgpg-error.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libgpg-error.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libwind.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libwind.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libheimbase.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libheimbase.so.1
Reading symbols from /usr/lib/x86_64-linux-gnu/libhx509.so.5...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libhx509.so.5
Reading symbols from /usr/lib/x86_64-linux-gnu/libsqlite3.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libsqlite3.so.0
Reading symbols from /lib/x86_64-linux-gnu/libcrypt.so.1...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libcrypt-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libcrypt.so.1
Reading symbols from /lib/x86_64-linux-gnu/libnss_files.so.2...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libnss_files-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libnss_files.so.2
Reading symbols from /lib/x86_64-linux-gnu/libnss_compat.so.2...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libnss_compat-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libnss_compat.so.2
Reading symbols from /lib/x86_64-linux-gnu/libnsl.so.1...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libnsl-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libnsl.so.1
Reading symbols from /lib/x86_64-linux-gnu/libnss_nis.so.2...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/libnss_nis-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/libnss_nis.so.2
Reading symbols from /usr/lib/postgresql/9.1/lib/libafd.so...done.
Loaded symbols for /usr/lib/postgresql/9.1/lib/libafd.so
Reading symbols from /usr/lib/libgdal.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libgdal.so.1
Reading symbols from /usr/lib/libspatialindex.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libspatialindex.so.1
Reading symbols from /usr/lib/libboost_iostreams.so.1.46.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libboost_iostreams.so.1.46.1
Reading symbols from /usr/lib/libboost_serialization.so.1.46.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libboost_serialization.so.1.46.1
Reading symbols from /usr/lib/libproj.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libproj.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libQtSql.so.4...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libQtSql.so.4
Reading symbols from /usr/lib/x86_64-linux-gnu/libQtCore.so.4...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libQtCore.so.4
Reading symbols from /usr/lib/x86_64-linux-gnu/libstdc++.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libstdc++.so.6
Reading symbols from /lib/x86_64-linux-gnu/libgcc_s.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libgcc_s.so.1
Reading symbols from /usr/lib/libarmadillo.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libarmadillo.so.2
Reading symbols from /usr/lib/x86_64-linux-gnu/libpoppler.so.19...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libpoppler.so.19
Reading symbols from /usr/lib/libgeos_c.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libgeos_c.so.1
Reading symbols from /usr/lib/libepsilon.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libepsilon.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libodbc.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libodbc.so.1
Reading symbols from /usr/lib/x86_64-linux-gnu/libodbcinst.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libodbcinst.so.1
Reading symbols from /lib/x86_64-linux-gnu/libexpat.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libexpat.so.1
Reading symbols from /usr/lib/libxerces-c.so.28...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libxerces-c.so.28
Reading symbols from /usr/lib/x86_64-linux-gnu/libjasper.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libjasper.so.1
Reading symbols from /usr/lib/libnetcdf.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libnetcdf.so.6
Reading symbols from /usr/lib/libhdf5.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libhdf5.so.6
Reading symbols from /usr/lib/libmfhdfalt.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libmfhdfalt.so.0
Reading symbols from /usr/lib/libdfalt.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libdfalt.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libgif.so.4...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libgif.so.4
Reading symbols from /usr/lib/x86_64-linux-gnu/libjpeg.so.8...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libjpeg.so.8
Reading symbols from /lib/x86_64-linux-gnu/libpng12.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libpng12.so.0
Reading symbols from /usr/lib/libpq.so.5...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libpq.so.5
Reading symbols from /usr/lib/x86_64-linux-gnu/libdapclient.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libdapclient.so.3
Reading symbols from /usr/lib/x86_64-linux-gnu/libdap.so.11...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libdap.so.11
Reading symbols from /usr/lib/libspatialite.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libspatialite.so.3
Reading symbols from /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.4...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.4
Reading symbols from /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libmysqlclient.so.18
Reading symbols from /lib/x86_64-linux-gnu/libbz2.so.1.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libbz2.so.1.0
Reading symbols from /lib/x86_64-linux-gnu/librt.so.1...Reading symbols from /usr/lib/debug/lib/x86_64-linux-gnu/librt-2.15.so...done.
done.
Loaded symbols for /lib/x86_64-linux-gnu/librt.so.1
Reading symbols from /lib/x86_64-linux-gnu/libglib-2.0.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libglib-2.0.so.0
Reading symbols from /usr/lib/libblas.so.3gf...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libblas.so.3gf
Reading symbols from /usr/lib/liblapack.so.3gf...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/liblapack.so.3gf
Reading symbols from /usr/lib/x86_64-linux-gnu/liblcms2.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/liblcms2.so.2
Reading symbols from /usr/lib/x86_64-linux-gnu/libtiff.so.4...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libtiff.so.4
Reading symbols from /usr/lib/x86_64-linux-gnu/libfreetype.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libfreetype.so.6
Reading symbols from /usr/lib/x86_64-linux-gnu/libfontconfig.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libfontconfig.so.1
Reading symbols from /usr/lib/libgeos-3.3.8.so...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libgeos-3.3.8.so
Reading symbols from /usr/lib/x86_64-linux-gnu/libltdl.so.7...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libltdl.so.7
Reading symbols from /usr/lib/libicuuc.so.48...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libicuuc.so.48
Reading symbols from /usr/lib/libhdf5_hl.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libhdf5_hl.so.6
Reading symbols from /usr/lib/x86_64-linux-gnu/libfreexl.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libfreexl.so.1
Reading symbols from /usr/lib/x86_64-linux-gnu/libidn.so.11...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libidn.so.11
Reading symbols from /usr/lib/x86_64-linux-gnu/librtmp.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/librtmp.so.0
Reading symbols from /lib/x86_64-linux-gnu/libpcre.so.3...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libpcre.so.3
Reading symbols from /usr/lib/x86_64-linux-gnu/libgfortran.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libgfortran.so.3
Reading symbols from /usr/lib/libicudata.so.48...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libicudata.so.48
Reading symbols from /usr/lib/x86_64-linux-gnu/libquadmath.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libquadmath.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/gconv/UTF-16.so...Reading symbols from /usr/lib/debug/usr/lib/x86_64-linux-gnu/gconv/UTF-16.so...done.
done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/gconv/UTF-16.so
Reading symbols from /usr/lib/libicui18n.so.48...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libicui18n.so.48
Reading symbols from /usr/lib/x86_64-linux-gnu/qt4/plugins/sqldrivers/libqsqlite.so...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/qt4/plugins/sqldrivers/libqsqlite.so
Reading symbols from /usr/lib/x86_64-linux-gnu/qt4/plugins/sqldrivers/libqsqlpsql.so...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/qt4/plugins/sqldrivers/libqsqlpsql.so
0x00002b3b1ed34c22 in __libc_recv (fd=8, buf=0xb0da00, n=8192, 
flags=<optimized out>) at ../sysdeps/unix/sysv/linux/x86_64/recv.c:30
30  ../sysdeps/unix/sysv/linux/x86_64/recv.c: No such file or directory.

尝试设置断点并获取错误：

(gdb) b libafd_traj_quality
Cannot access memory at address 0x26c01f
(gdb)

如何在函数上设置断点？？？

其他信息：

# cat /proc/22648/maps  | grep libafd
2b3b2556e000-2b3b25a82000 r-xp 00000000 08:01 5379086                    /usr/lib/postgresql/9.1/lib/libafd.so
2b3b25a82000-2b3b25c82000 ---p 00514000 08:01 5379086                    /usr/lib/postgresql/9.1/lib/libafd.so
2b3b25c82000-2b3b25c88000 r--p 00514000 08:01 5379086                    /usr/lib/postgresql/9.1/lib/libafd.so
2b3b25c88000-2b3b25c9a000 rw-p 0051a000 08:01 5379086                    /usr/lib/postgresql/9.1/lib/libafd.so

# nm -as /usr/lib/postgresql/9.1/lib/libafd.so | grep libafd_traj_quality
00000000003d4788 r _ZZ28pg_finfo_libafd_traj_qualityE8my_finfo
000000000026c01f T libafd_traj_quality
000000000026c012 T pg_finfo_libafd_traj_quality

---

非常感谢您提供的任何帮助

我认为问题可能在于您告诉gdb调试共享库，通常您会给它一个可执行文件的名称。但是，由于您正在调试一个已经运行的进程，您甚至不必这样做。尝试附加到进程，而不指定文件，只指定PID

(gdb) b libafd_traj_quality
Cannot access memory at address 0x26c01f
(gdb)

# cat /proc/22648/maps  | grep libafd
2b3b2556e000-2b3b25a82000 r-xp 00000000 08:01 5379086                    /usr/lib/postgresql/9.1/lib/libafd.so
2b3b25a82000-2b3b25c82000 ---p 00514000 08:01 5379086                    /usr/lib/postgresql/9.1/lib/libafd.so
2b3b25c82000-2b3b25c88000 r--p 00514000 08:01 5379086                    /usr/lib/postgresql/9.1/lib/libafd.so
2b3b25c88000-2b3b25c9a000 rw-p 0051a000 08:01 5379086                    /usr/lib/postgresql/9.1/lib/libafd.so

# nm -as /usr/lib/postgresql/9.1/lib/libafd.so | grep libafd_traj_quality
00000000003d4788 r _ZZ28pg_finfo_libafd_traj_qualityE8my_finfo
000000000026c01f T libafd_traj_quality
000000000026c012 T pg_finfo_libafd_traj_quality