master> INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so'; Could not open required defaults file: master.cnf Fatal error in defaults handling. Program aborted *** glibc detected *** mysqld: munmap_chunk(): invalid pointer: 0xbfc7e134 *** ======= Backtrace: ========= /lib/libc.so.6[0x1c11e1] mysqld(my_free+0x1d)[0x857ae9d] mysqld(free_root+0xd9)[0x8573169] mysqld(free_defaults+0x5b)[0x856298b] mysqld(_Z20mysql_install_pluginP3THDPK19st_mysql_lex_stringS3_+0x2d0)[0x81a7fd0] mysqld(_Z21mysql_execute_commandP3THD+0x190a)[0x8197e5a] mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x161)[0x819d831] mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1412)[0x819f562] mysqld(_Z10do_commandP3THD+0xdf)[0x819fcbf] mysqld(_Z24do_handle_one_connectionP3THD+0x259)[0x823e299] mysqld(handle_one_connection+0x4f)[0x823e62f] /lib/libpthread.so.0(-0xffd196e7)[0x116919] /lib/libc.so.6(clone+0x5e)[0x22fe5e] ======= Memory map: ======== 00110000-00127000 r-xp 00000000 fd:00 533815 /lib/libpthread-2.12.so 00127000-00128000 r--p 00016000 fd:00 533815 /lib/libpthread-2.12.so 00128000-00129000 rw-p 00017000 fd:00 533815 /lib/libpthread-2.12.so 00129000-0012b000 rw-p 00000000 00:00 0 00130000-0014e000 r-xp 00000000 fd:00 533806 /lib/ld-2.12.so 0014e000-0014f000 r--p 0001d000 fd:00 533806 /lib/ld-2.12.so 0014f000-00150000 rw-p 0001e000 fd:00 533806 /lib/ld-2.12.so 00152000-002d8000 r-xp 00000000 fd:00 533807 /lib/libc-2.12.so 002d8000-002da000 r--p 00185000 fd:00 533807 /lib/libc-2.12.so 002da000-002db000 rw-p 00187000 fd:00 533807 /lib/libc-2.12.so 002db000-002de000 rw-p 00000000 00:00 0 002de000-002e5000 r-xp 00000000 fd:00 663343 /usr/local/mysql-5.5.6-rc-linux2.6-i686/lib/plugin/semisync_master.so 002e5000-002e6000 rw-p 00007000 fd:00 663343 /usr/local/mysql-5.5.6-rc-linux2.6-i686/lib/plugin/semisync_master.so 002f7000-002f8000 r-xp 00000000 00:00 0 [vdso] 002fd000-00300000 r-xp 00000000 fd:00 533809 /lib/libdl-2.12.so 00300000-00301000 r--p 00002000 fd:00 533809 /lib/libdl-2.12.so 00301000-00302000 rw-p 00003000 fd:00 533809 /lib/libdl-2.12.so 00304000-0030b000 r-xp 00000000 fd:00 533818 /lib/librt-2.12.so 0030b000-0030c000 r--p 00006000 fd:00 533818 /lib/librt-2.12.so 0030c000-0030d000 rw-p 00007000 fd:00 533818 /lib/librt-2.12.so 0030f000-00337000 r-xp 00000000 fd:00 533826 /lib/libm-2.12.so 00337000-00338000 r--p 00027000 fd:00 533826 /lib/libm-2.12.so 00338000-00339000 rw-p 00028000 fd:00 533826 /lib/libm-2.12.so 00339000-00356000 r-xp 00000000 fd:00 533835 /lib/libgcc_s-4.4.4-20100503.so.1 00356000-00357000 rw-p 0001d000 fd:00 533835 /lib/libgcc_s-4.4.4-20100503.so.1 00b99000-00b9a000 r-xp 00000000 fd:00 524757 /lib/libaio.so.1.0.1 00b9a000-00b9b000 rw-p 00000000 fd:00 524757 /lib/libaio.so.1.0.1 00d4c000-00d91000 r-xp 00000000 fd:00 533830 /lib/libfreebl3.so 00d91000-00d92000 rw-p 00045000 fd:00 533830 /lib/libfreebl3.so 00d92000-00d96000 rw-p 00000000 00:00 0 00db4000-00dbb000 r-xp 00000000 fd:00 533831 /lib/libcrypt-2.12.so 00dbb000-00dbc000 r--p 00007000 fd:00 533831 /lib/libcrypt-2.12.so 00dbc000-00dbd000 rw-p 00008000 fd:00 533831 /lib/libcrypt-2.12.so 00dbd000-00de4000 rw-p 00000000 00:00 0 00fba000-00fc6000 r-xp 00000000 fd:00 524420 /lib/libnss_files-2.12.so 00fc6000-00fc7000 r--p 0000b000 fd:00 524420 /lib/libnss_files-2.12.so 00fc7000-00fc8000 rw-p 0000c000 fd:00 524420 /lib/libnss_files-2.12.so 08048000-088ad000 r-xp 00000000 fd:00 656928 /usr/local/mysql-5.5.6-rc-linux2.6-i686/bin/mysqld 088ad000-08975000 rw-p 00864000 fd:00 656928 /usr/local/mysql-5.5.6-rc-linux2.6-i686/bin/mysqld 08975000-08992000 rw-p 00000000 00:00 0 0a759000-0ae5a000 rw-p 00000000 00:00 0 [heap] a5100000-a5130000 rw-p 00000000 00:00 0 a5130000-a5200000 ---p 00000000 00:00 0 a5208000-a5209000 ---p 00000000 00:00 0 a5209000-a5239000 rw-p 00000000 00:00 0 a5239000-a523a000 ---p 00000000 00:00 0 a523a000-a526a000 rw-p 00000000 00:00 0 a526a000-a526b000 ---p 00000000 00:00 0 a526b000-a529b000 rw-p 00000000 00:00 0 a529b000-a529c000 ---p 00000000 00:00 0 a529c000-a5c9c000 rw-p 00000000 00:00 0 a5c9c000-a5c9d000 ---p 00000000 00:00 0 a5c9d000-a669d000 rw-p 00000000 00:00 0 a669d000-a669e000 ---p 00000000 00:00 0 a669e000-a709e000 rw-p 00000000 00:00 0 a709e000-a709f000 ---p 00000000 00:00 0 a709f000-a7d2d000 rw-p 00000000 00:00 0 a7d2d000-a7d2e000 ---p 00000000 00:00 0 a7d2e000-a872e000 rw-p 00000000 00:00 0 a872e000-a872f000 ---p 00000000 00:00 0 a872f000-a912f000 rw-p 00000000 00:00 0 a912f000-a9130000 ---p 00000000 00:00 0 a9130000-a9b30000 rw-p 00000000 00:00 0 a9b30000-a9b31000 ---p 00000000 00:00 0 a9b31000-aa531000 rw-p 00000000 00:00 0 aa531000-aa532000 ---p 00000000 00:00 0 aa532000-aaf32000 rw-p 00000000 00:00 0 aaf32000-aaf33000 ---p 00000000 00:00 0 aaf33000-ab933000 rw-p 00000000 00:00 0 ab933000-ab934000 ---p 00000000 00:00 0 ab934000-ac334000 rw-p 00000000 00:00 0 ac334000-ac335000 ---p 00000000 00:00 0 ac335000-acd35000 rw-p 00000000 00:00 0 acd35000-acd36000 ---p 00000000 00:00 0 acd36000-b6d00000 rw-p 00000000 00:00 0 b6d00000-b6d21000 rw-p 00000000 00:00 0 b6d21000-b6e00000 ---p 00000000 00:00 0 b6ebf000-b6ec0000 ---p 00000000 00:00 0 b6ec0000-b78c3000 rw-p 00000000 00:00 0 b78d3000-b78d4000 rw-p 00000000 00:00 0 bfc6b000-bfc80000 rw-p 00000000 00:00 0 [stack] 100929 16:45:20 - mysqld got signal 6 ; This could be because you hit a bug. It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured. This error can also be caused by malfunctioning hardware. We will try our best to scrape up some info that will hopefully help diagnose the problem, but since we have already crashed, something is definitely wrong and this may fail. key_buffer_size=8388608 read_buffer_size=131072 max_used_connections=2 max_threads=151 thread_count=2 connection_count=2 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 337834 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. thd: 0xadc4858 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 = 0xa5269358 thread_stack 0x30000 mysqld(my_print_stacktrace+0x33)[0x857f173] mysqld(handle_segfault+0x444)[0x811ba44] [0x2f7400] /lib/libc.so.6(abort+0x17a)[0x17e64a] /lib/libc.so.6[0x1bad9d] /lib/libc.so.6[0x1c11e1] mysqld(my_free+0x1d)[0x857ae9d] mysqld(free_root+0xd9)[0x8573169] mysqld(free_defaults+0x5b)[0x856298b] mysqld(_Z20mysql_install_pluginP3THDPK19st_mysql_lex_stringS3_+0x2d0)[0x81a7fd0] mysqld(_Z21mysql_execute_commandP3THD+0x190a)[0x8197e5a] mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x161)[0x819d831] mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1412)[0x819f562] mysqld(_Z10do_commandP3THD+0xdf)[0x819fcbf] mysqld(_Z24do_handle_one_connectionP3THD+0x259)[0x823e299] mysqld(handle_one_connection+0x4f)[0x823e62f] /lib/libpthread.so.0(-0xffd196e7)[0x116919] /lib/libc.so.6(clone+0x5e)[0x22fe5e] Trying to get some variables. Some pointers may be invalid and cause the dump to abort... thd->query at 0xae2eff0 = INSTALL PLUGIN rpl_semi_sync_master SONAME 'semisync_master.so' thd->thread_id=2 thd->killed=NOT_KILLED The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains information that should help you find out what is causing the crash. ERROR 2013 (HY000): Lost connection to MySQL server during query