Changes between Version 11 and Version 12 of AndreesStuff

Timestamp:

Sep 26, 2006, 2:21:06 PM (18 years ago)

Author:

andree

Comment:

--

AndreesStuff

@@ -164 +164 @@
 == General ==
 
-Backtraces can be very useful to trouble-shoot issues like segmentation faults. To create a useful backtrace, you need gdb (the GNU Debugger) installed and an application (and possibly libraries) with debugging symbols built in. The following will explain how to do this.
+Backtraces can be very helpful when trouble-shooting issues like segmentation faults. To create a useful backtrace, you need gdb (the GNU Debugger) installed and an application (and possibly libraries) with debugging symbols built in. The following will explain how to do this.
 
 == gdb ==
@@ -171 +171 @@
 
 {{{
-apt-get gdb
+apt-get install gdb
 }}}
 
@@ -185 +185 @@
 == mondoarchive/mondorescue with debugging symbols ==
 
-To get mondoarchive and mondorescue with debugging symbols built in, you need to build from the source.
-
-Get the latest stable mondo source package from ftp://ftp.mondorescue.org/src/, e.g. mondo-2.0.9.tar.gz, unpack:
+To get '''mondoarchive''' and '''mondorescue''' with debugging symbols built in, you need to build from the source.
+
+Get the latest stable mondo source package from '''ftp://ftp.mondorescue.org/src/''', e.g. '''mondo-2.0.9.tar.gz''', unpack:
 
 {{{
@@ -197 +197 @@
 {{{
 cd mondo-2.0.9
+./configure --prefix=/usr
 make
 }}}
@@ -202 +203 @@
 You will end up with binary in the following locations which are non-stripped, i.e. they contain debugging symbols:
 {{{
-file
+file mondo/mondoarchive/mondoarchive
+mondo/mondoarchive/mondoarchive: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.2.0, dynamically linked (uses shared libs), not stripped
 }}}
 
@@ -208 +210 @@
 
 {{{
-file
-}}}
-
-Make backups of the original mondoarchive and mondorestore binaries and copy they newly created over the original ones.
-
-== mondoarchive ==
-
-== mondorestore ==
-
+file mondo/mondorestore/mondorestore
+mondo/mondorestore/mondorestore: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.2.0, dynamically linked (uses shared libs), not stripped
+}}}
+
+Make backups of the original '''mondoarchive''' and '''mondorestore''' binaries and copy they newly created over the original ones.
+
+== Trouble-Shooting mondoarchive ==
+
+The best approach is to run the '''mondoarchive''' binary you just created with debugging symbols built in from its location in the built directory under gdb. So:
+
+{{{
+cd mondo/mondoarchive
+gdb ./mondoarchive
+run <usual arguments you use>
+}}}
+
+When the segmentation fault happens, enter:
+
+{{{
+bt
+}}}
+
+and send the output to the list.
+
+== Trouble-Shooting mondorestore ==
+
+If you do partial restore onto a live system, the same approach as described for '''mondoarchive''' can be used.
+
+However, more likely you will experience a segmentation fault during restore. To run a backtrace in that situation proceeed as follows:
+
+First, you need a '''mondorestore''' binary with debugging symbols. This should already been taken care of if you copied the newly compiled binaries as described above. Next, you need to make sure that gdb is available on your restore media. To achieve this, add gdb to '''/etc/mindi/deplist.txt''' before doing a mondoarchive run.
+
+Boot the restore media into '''expert''' mode. Then start '''mondoarchive''' like this:
+
+{{{
+gdb /usr/sbin/mondorestore
+run
+}}}
+
+As described previously, once the segmentation fault happens, do:
+
+{{{
+bt
+}}}
+
+and send the output to the list. (If you can't get the backtrace copied as text, you can use a photo of the screen as the last resort.
+
+== Advanced Topics ==
+
+= Attaching to Running Processes =
+
+You can attach to a running process using:
+
+{{{
+attach <pid>
+}}}
+
+where <pid> is the process ID.
+
+This can be particulary useful when running '''mondoarchive''' with the '-g' or when running '''mondorestore'''.
+
+= Using libraries with debugging symbols =
+
+The libraries used by a binary can be determined using the ldd command, e.g.:
+
+{{{
+ldd /usr/sbin/mondoarchive
+                libmondo.so.2 => /usr/lib/libmondo.so.2 (0xb7f8d000)
+        libmondo-newt.so.1 => /usr/lib/libmondo-newt.so.1 (0xb7f82000)
+        libnewt.so.0.51 => /usr/lib/libnewt.so.0.51 (0xb7f71000)
+        libdl.so.2 => /lib/tls/libdl.so.2 (0xb7f6e000)
+        libpthread.so.0 => /lib/tls/libpthread.so.0 (0xb7f5f000)
+        libc.so.6 => /lib/tls/libc.so.6 (0xb7e2a000)
+        libslang.so.1-UTF8 => /lib/libslang.so.1-UTF8 (0xb7db7000)
+        libm.so.6 => /lib/tls/libm.so.6 (0xb7d94000)
+        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0xb7fea000)
+}}}
+
+some of those libraries may come with debugging symbols built in as an alternative package, others can be buiolt from scratch and installed with debugging sysmbols installed. Using your distribtuion's standard built process is probably a good idea for this.