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Anonymous, 2005-09-21 09:49

= How to report a bug =

If you find a bug in lighttpd you can help alot to find a fix for it by following some simple steps:


A backtrace is a trace of the function which have been called before lighttpd died.

The best way to generate such a backtrace is using [ valgrind]:

$ valgrind --tool=memcheck -v --log-file=lighttpd --num-callers=8 lighttpd -D -f ./lighttpd.conf

valgrind does many useful things while it waits for the server to crash:

  • checks for uninitialized variables
  • checks for out-of-bounds access
  • and many more

valgrind does not normally produce large log files and does not seem to degrade lightthpd's throughput much. Meaning, it's a very good alternative when debugging on busy servers as compared to strace.

If you can't use valgrind there is another way to generate a backtrace:

$ gdb lighttpd
(gdb) r -D -f lighttpd.conf
(gdb) bt


strace is the name of the syscall-tracer on Linux. Every Unix-like OS provides a utility to collect information about system call like open, write, close and so on.

The have different names like

  • strace
  • truss
  • ktrace (then kdump to get output)

If strace is available it is prefered as it provides the most useful information. Execute it like:

$ strace -olighttpd.trace -tt -s 4000 lighttpd -D -f ./lighttpd.conf

It will generate a file called lighttpd.trace.

If you have a running instance of lighttpd and want to see what lighttpd is doing you can attach strace to the process:

$ strace -olighttpd.trace -tt -s 4000 -p <pidof-lighttpd>


If you experience that lighttpd is using more than 1Gb of RAM you might have spotted a memleak. Valgrind, our valuable helper, can help you to provide the necessary information to fix it.

$ valgrind --tool=memcheck -v --log-file=lighttpd --num-callers=8 \
--leak-check=yes --show-reachable=yes \
lighttpd -D -f ./lighttpd.conf

Beware that this will use alot of memory and will slow down the process. You might not be able to run this on a production system with real load.

Writing a bug report

If you have generated a backtrace or a syscall-trace please make sure that you can reproduce the problem. Otherwise it will be really hard for the developers to fix the problem for you.

If possible open a [ new ticket]

If the report contains sensitive data you might also send it directly to: mailto:

Updated by Anonymous about 18 years ago · 4 revisions