Debugging a MySQL Server mysqld got signal 11; Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 0x41fd0110 thread_stack 0x40000 mysqld(my_print_stacktrace+0x32)[0x9da402] mysqld(handle_segfault+0x28a)[0x6648e9] /lib/libpthread.so.0[0x7f1a5af000f0] /lib/libc.so.6(strcmp+0x2)[0x7f1a5a10f0f2] mysqld(_Z21check_change_passwordP3THDPKcS2_Pcj+0x7c)[0x7412cb] mysqld(_ZN16set_var_password5checkEP3THD+0xd0)[0x688354] mysqld(_Z17sql_set_variablesP3THDP4ListI12set_var_baseE+0x68)[0x688494] mysqld(_Z21mysql_execute_commandP3THD+0x41a0)[0x67a170] mysqld(_Z11mysql_parseP3THDPKcjPS2_+0x282)[0x67f0ad] mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0xbb7[0x67fdf8] mysqld(_Z10do_commandP3THD+0x24d)[0x6811b6] mysqld(handle_one_connection+0x11c)[0x66e05e] mysqld got signal 11; Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 0x41fd0110 thread_stack 0x40000 [0x9da402] [0x6648e9] [0x7f1a5af000f0] [0x7f1a5a10f0f2] [0x7412cb] [0x688354] [0x688494] [0x67a170] [0x67f0ad] [0x67fdf8] [0x6811b6] [0x66e05e] If resolution of function names for the trace fails, the trace contains less information: Newer versions of  glibc  stack trace functions also print the address as relative to the object. On  glibc - based systems (Linux), the trace for an unexpected exit within a plugin looks something like: To translate the relative address ( +0x9a6 ) into a file name and line number, use this command: The  addr2line  utility is part of the  binutils  package on Linux. On Solaris, the procedure is similar. The Solaris  printstack()  already prints relative addresses: To translate, use this command: Windows already prints the address, function name and line: plugin/auth/auth_test_plugin.so(+0x9a6)[0x7ff4d11c29a6] shell>  addr2line -fie auth_test_plugin.so 0x9a6 auth_test_plugin mysql-trunk/plugin/auth/test_plugin.c:65 plugin/auth/auth_test_plugin.so:0x1510 shell>  gaddr2line -fie auth_test_plugin.so 0x1510 mysql-trunk/plugin/auth/test_plugin.c:88 000007FEF07E10A4 auth_test_plugin.dll!auth_test_plugin()[test_plugin.c:72] 1157