The backtrace module is not enabled by default. You should compile it explicitly:

./configure --with-backtrace_module.

It can be used to dump backtrace of nginx in case a worker process exits abnormally, e.g. when some signal is received (SIGABR, SIGBUS, SIGFPE, SIGILL, SIGIOT, SIGSEGV). It's quite handy for debugging purpose.

This module requires the backtrace(3) function in glibc. You can't enable it on systems lack of this function (FreeBSD, Darwin).


Syntax: backtrace_log log_path
Default: backtrace_log error.log
Context: main

Specify the log file name of backtrace.

backtrace_log /path/to/backtrace.log

Syntax: backtrace_max_stack_size size
Default: backtrace_max_stack_size 30
Context: main

Specify the maximum stack depth for backtrace