1. i am using some modules, when i stop the agent (/etc/init.d/zabbix-agent stop)on CentOS 5.x , it crashed.

2. on CentOS 6.x , it works well

3. log:
22570:20150305:102340.225 Got signal [signal:15(SIGTERM),sender_pid:22624,sender_uid:0,reason:0]. Exiting ...
22570:20150305:102340.225 zbx_on_exit() called
22571:20150305:102340.225 Got signal [signal:15(SIGTERM),sender_pid:22570,sender_uid:101,reason:0]. Exiting ...
22572:20150305:102340.225 Got signal [signal:15(SIGTERM),sender_pid:22570,sender_uid:101,reason:0]. Exiting ...
22570:20150305:102340.226 Zabbix Agent stopped. Zabbix 2.4.4 (revision 52341).
22570:20150305:102340.226 In unload_modules()
22570:20150305:102340.226 Got signal [signal:11(SIGSEGV),reason:2,refaddr:0x7fff6f686100]. Crashing ...
22570:20150305:102340.226 ====== Fatal information: ======
22570:20150305:102340.226 Program counter: 0x7fff6f686100
22570:20150305:102340.226 === Registers: ===
22570:20150305:102340.226 r8 = 7fff6f684a70 = 140735062493808 = 140735062493808
22570:20150305:102340.226 r9 = 1fb51ca8 = 531963048 = 531963048
22570:20150305:102340.226 r10 = 0 = 0 = 0
22570:20150305:102340.226 r11 = ffffffff = 4294967295 = 4294967295
22570:20150305:102340.226 r12 = 1 = 1 = 1
22570:20150305:102340.226 r13 = 7fff6f686100 = 140735062499584 = 140735062499584
22570:20150305:102340.226 r14 = 0 = 0 = 0
22570:20150305:102340.226 r15 = 0 = 0 = 0
22570:20150305:102340.226 rdi = 35b781d480 = 230712005760 = 230712005760
22570:20150305:102340.226 rsi = 0 = 0 = 0
22570:20150305:102340.226 rbp = 7fff6f684da0 = 140735062494624 = 140735062494624
22570:20150305:102340.226 rbx = 1fb51870 = 531961968 = 531961968
22570:20150305:102340.226 rdx = 7fff6f686100 = 140735062499584 = 140735062499584
22570:20150305:102340.226 rax = 0 = 0 = 0
22570:20150305:102340.226 rcx = 0 = 0 = 0
22570:20150305:102340.226 rsp = 7fff6f684d88 = 140735062494600 = 140735062494600
22570:20150305:102340.226 rip = 7fff6f686100 = 140735062499584 = 140735062499584
22570:20150305:102340.226 efl = 10246 = 66118 = 66118
22570:20150305:102340.226 csgsfs = 33 = 51 = 51
22570:20150305:102340.226 err = 15 = 21 = 21
22570:20150305:102340.226 trapno = e = 14 = 14
22570:20150305:102340.226 oldmask = 14000 = 81920 = 81920
22570:20150305:102340.226 cr2 = 7fff6f686100 = 140735062499584 = 140735062499584
22570:20150305:102340.226 === Backtrace: ===
22570:20150305:102340.227 3: zabbix_agentd(print_fatal_info+0xd9) [0x4250c9]
22570:20150305:102340.227 2: zabbix_agentd [0x425889]
22570:20150305:102340.227 1: /lib64/libc.so.6 [0x35b7a30030]
22570:20150305:102340.227 0: [0x7fff6f686100]
22570:20150305:102340.227 === Memory map: ===
22570:20150305:102340.227 00400000-00444000 r-xp 00000000 fd:00 3020501 /usr/sbin/zabbix_agentd
22570:20150305:102340.227 00644000-00646000 rw-p 00044000 fd:00 3020501 /usr/sbin/zabbix_agentd
22570:20150305:102340.227 00646000-0064b000 rw-p 00646000 00:00 0
22570:20150305:102340.227 1fb4e000-1fb6f000 rw-p 1fb4e000 00:00 0 [heap]
22570:20150305:102340.227 35b7600000-35b761c000 r-xp 00000000 fd:00 3211289 /lib64/ld-2.5.so
22570:20150305:102340.227 35b781c000-35b781d000 r--p 0001c000 fd:00 3211289 /lib64/ld-2.5.so
22570:20150305:102340.227 35b781d000-35b781e000 rw-p 0001d000 fd:00 3211289 /lib64/ld-2.5.so
22570:20150305:102340.227 35b7a00000-35b7b4f000 r-xp 00000000 fd:00 3211291 /lib64/libc-2.5.so
22570:20150305:102340.227 35b7b4f000-35b7d4f000 ---p 0014f000 fd:00 3211291 /lib64/libc-2.5.so
22570:20150305:102340.227 35b7d4f000-35b7d53000 r--p 0014f000 fd:00 3211291 /lib64/libc-2.5.so
22570:20150305:102340.227 35b7d53000-35b7d54000 rw-p 00153000 fd:00 3211291 /lib64/libc-2.5.so
22570:20150305:102340.227 35b7d54000-35b7d59000 rw-p 35b7d54000 00:00 0
22570:20150305:102340.227 35b7e00000-35b7e02000 r-xp 00000000 fd:00 3211321 /lib64/libdl-2.5.so
22570:20150305:102340.227 35b7e02000-35b8002000 ---p 00002000 fd:00 3211321 /lib64/libdl-2.5.so
22570:20150305:102340.227 35b8002000-35b8003000 r--p 00002000 fd:00 3211321 /lib64/libdl-2.5.so
22570:20150305:102340.227 35b8003000-35b8004000 rw-p 00003000 fd:00 3211321 /lib64/libdl-2.5.so
22570:20150305:102340.227 35b8200000-35b8216000 r-xp 00000000 fd:00 3212869 /lib64/libpthread-2.5.so
22570:20150305:102340.227 35b8216000-35b8416000 ---p 00016000 fd:00 3212869 /lib64/libpthread-2.5.so
22570:20150305:102340.227 35b8416000-35b8417000 r--p 00016000 fd:00 3212869 /lib64/libpthread-2.5.so
22570:20150305:102340.228 35b8417000-35b8418000 rw-p 00017000 fd:00 3212869 /lib64/libpthread-2.5.so
22570:20150305:102340.228 35b8418000-35b841c000 rw-p 35b8418000 00:00 0
22570:20150305:102340.228 35b8a00000-35b8a82000 r-xp 00000000 fd:00 3211352 /lib64/libm-2.5.so
22570:20150305:102340.228 35b8a82000-35b8c81000 ---p 00082000 fd:00 3211352 /lib64/libm-2.5.so
22570:20150305:102340.228 35b8c81000-35b8c82000 r--p 00081000 fd:00 3211352 /lib64/libm-2.5.so
22570:20150305:102340.228 35b8c82000-35b8c83000 rw-p 00082000 fd:00 3211352 /lib64/libm-2.5.so
22570:20150305:102340.228 35b8e00000-35b8e07000 r-xp 00000000 fd:00 3212870 /lib64/librt-2.5.so
22570:20150305:102340.228 35b8e07000-35b9007000 ---p 00007000 fd:00 3212870 /lib64/librt-2.5.so
22570:20150305:102340.228 35b9007000-35b9008000 r--p 00007000 fd:00 3212870 /lib64/librt-2.5.so
22570:20150305:102340.228 35b9008000-35b9009000 rw-p 00008000 fd:00 3212870 /lib64/librt-2.5.so
22570:20150305:102340.228 35b9e00000-35b9e0d000 r-xp 00000000 fd:00 3211305 /lib64/libgcc_s-4.1.2-20080825.so.1
22570:20150305:102340.228 35b9e0d000-35ba00d000 ---p 0000d000 fd:00 3211305 /lib64/libgcc_s-4.1.2-20080825.so.1
22570:20150305:102340.228 35ba00d000-35ba00e000 rw-p 0000d000 fd:00 3211305 /lib64/libgcc_s-4.1.2-20080825.so.1
22570:20150305:102340.228 35ba200000-35ba211000 r-xp 00000000 fd:00 3211451 /lib64/libresolv-2.5.so
22570:20150305:102340.228 35ba211000-35ba411000 ---p 00011000 fd:00 3211451 /lib64/libresolv-2.5.so
22570:20150305:102340.228 35ba411000-35ba412000 r--p 00011000 fd:00 3211451 /lib64/libresolv-2.5.so
22570:20150305:102340.228 35ba412000-35ba413000 rw-p 00012000 fd:00 3211451 /lib64/libresolv-2.5.so
22570:20150305:102340.228 35ba413000-35ba415000 rw-p 35ba413000 00:00 0
22570:20150305:102340.228 2b4a1323b000-2b4a1323e000 rw-p 2b4a1323b000 00:00 0
22570:20150305:102340.228 2b4a13251000-2b4a13254000 rw-p 2b4a13251000 00:00 0
22570:20150305:102340.228 2b4a13254000-2b4a1325e000 r-xp 00000000 fd:00 3211290 /lib64/libnss_files-2.5.so
22570:20150305:102340.228 2b4a1325e000-2b4a1345d000 ---p 0000a000 fd:00 3211290 /lib64/libnss_files-2.5.so
22570:20150305:102340.228 2b4a1345d000-2b4a1345e000 r--p 00009000 fd:00 3211290 /lib64/libnss_files-2.5.so
22570:20150305:102340.228 2b4a1345e000-2b4a1345f000 rw-p 0000a000 fd:00 3211290 /lib64/libnss_files-2.5.so
22570:20150305:102340.228 2b4a1345f000-2b4a13462000 r-xp 00000000 fd:00 460392 /etc/zabbix/modules/ipvs.so
22570:20150305:102340.228 2b4a13462000-2b4a13661000 ---p 00003000 fd:00 460392 /etc/zabbix/modules/ipvs.so
22570:20150305:102340.228 2b4a13661000-2b4a13662000 rw-p 00002000 fd:00 460392 /etc/zabbix/modules/ipvs.so
22570:20150305:102340.228 2b4a13662000-2b4a136aa000 rw-s 00000000 00:09 4751365 /SYSV6c000705 (deleted)
22570:20150305:102340.228 2b4a136aa000-2b4a136ab000 rw-p 2b4a136aa000 00:00 0
22570:20150305:102340.228 7fff6f672000-7fff6f687000 rw-p 7ffffffe9000 00:00 0 [stack]
22570:20150305:102340.228 7fff6f7f5000-7fff6f7f8000 r-xp 7fff6f7f5000 00:00 0 [vdso]
22570:20150305:102340.228 ffffffffff600000-ffffffffffe00000 ---p 00000000 00:00 0 [vsyscall]
22570:20150305:102340.228 ================================
22570:20150305:102340.228 Please consider attaching a disassembly listing to your bug report.
22570:20150305:102340.228 This listing can be produced with, e.g., objdump -DSswx zabbix_agentd.
22570:20150305:102340.229 ================================