/usr/share/doc/apache2/README.backtrace is in apache2 2.4.18-2ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 | If apache crashes or freezes, it is helpful if you include a backtrace in the
bug report.
In case of a crash, do the following:
1) Install the packages apache2-dbg libapr1-dbg libaprutil1-dbg gdb.
2) Add "CoreDumpDirectory /var/cache/apache2/core" to your apache configuration.
3) Execute as root:
mkdir -p /var/cache/apache2/core
chown www-data: /var/cache/apache2/core
/etc/init.d/apache2 stop
ulimit -c unlimited
/etc/init.d/apache2 start
4) Do whatever it takes to reproduce the crash. There should now be the file
/var/cache/apache2/core .
5) If you use a forking MPM (e.g. mod_prefork), execute:
gdb /usr/sbin/apache2 /var/cache/apache2/core/core
(gdb) bt full
...
(gdb) quit
If you use a threaded mpm (mod_worker, mod_event), execute:
gdb /usr/sbin/apache2 /var/cache/apache2/core/core
(gdb) thread apply all bt full
...
(gdb) quit
Include the backtrace in the bug report.
6) Undo the change to your configuration, uninstall the debug packages, remove
/var/cache/apache2/core
In case of a hanging process, you don't need a core dump and you can skip steps 2 and 3.
4) Reproduce the problem. Get the pid of a hanging process.
5) Start gdb with
gdb -p pid
and continue as described above. It may also be helpful to include the output of
strace -p pid
|