Supplying a non-existend user to proc.mem[procname,username] kills the agent.

Disassembly listing is attached to this bugreport.

16299:20120822:073322.767 Requested [proc.mem[java,geres,,tomcat]]
16299:20120822:073322.768 Got signal [signal:11(SIGSEGV),reason:1,refaddr:(nil)]. Crashing ...
16299:20120822:073322.768 ====== Fatal information: ======
16299:20120822:073322.768 Program counter: (nil)
16299:20120822:073322.768 === Registers: ===
16299:20120822:073322.768 r8 = 7fff7b279810 = 140735259580432 = 140735259580432
16299:20120822:073322.768 r9 = 0 = 0 = 0
16299:20120822:073322.768 r10 = 5e9b40 = 6200128 = 6200128
16299:20120822:073322.768 r11 = 2b02563bbf70 = 47289036685168 = 47289036685168
16299:20120822:073322.768 r12 = 7fff7b279818 = 140735259580440 = 140735259580440
16299:20120822:073322.768 r13 = 7fff7b280cd8 = 140735259610328 = 140735259610328
16299:20120822:073322.768 r14 = 7fff7b280cb8 = 140735259610296 = 140735259610296
16299:20120822:073322.768 r15 = 3 = 3 = 3
16299:20120822:073322.768 rdi = 1e = 30 = 30
16299:20120822:073322.768 rsi = 7fff7b2798b0 = 140735259580592 = 140735259580592
16299:20120822:073322.768 rbp = 2b0256624040 = 47289039208512 = 47289039208512
16299:20120822:073322.768 rbx = 5e3150 = 6173008 = 6173008
16299:20120822:073322.768 rdx = 800000 = 8388608 = 8388608
16299:20120822:073322.768 rax = 5e3150 = 6173008 = 6173008
16299:20120822:073322.768 rcx = 2b0256382fb7 = 47289036451767 = 47289036451767
16299:20120822:073322.768 rsp = 7fff7b279608 = 140735259579912 = 140735259579912
16299:20120822:073322.769 rip = 0 = 0 = 0
16299:20120822:073322.769 efl = 10207 = 66055 = 66055
16299:20120822:073322.769 csgsfs = 33 = 51 = 51
16299:20120822:073322.769 err = 14 = 20 = 20
16299:20120822:073322.769 trapno = e = 14 = 14
16299:20120822:073322.769 oldmask = 0 = 0 = 0
16299:20120822:073322.769 cr2 = 0 = 0 = 0
16299:20120822:073322.769 === Backtrace: ===
16299:20120822:073322.769 2: [0x413b2d]
16299:20120822:073322.769 1: [0x413384]
16299:20120822:073322.769 0: [0x437b10]

16299:20120822:073322.769 === Memory map: ===
16299:20120822:073322.769 00400000-004d7000 r-xp 00000000 08:02 559141 /usr/local/sbin/zabbix_agentd
16299:20120822:073322.769 005d7000-005d9000 rw-p 000d7000 08:02 559141 /usr/local/sbin/zabbix_agentd
16299:20120822:073322.769 005d9000-00605000 rw-p 005d9000 00:00 0 [heap]
16299:20120822:073322.770 2b0256143000-2b0256144000 rw-p 2b0256143000 00:00 0
16299:20120822:073322.770 2b0256144000-2b025616f000 rw-s 00000000 00:08 458752 /SYSV6c02d411 (deleted)
16299:20120822:073322.770 2b025616f000-2b02561a4000 r--s 00000000 08:02 454776 /var/run/nscd/dbjGP5h3 (deleted)
16299:20120822:073322.770 2b02561be000-2b02561c8000 r-xp 00000000 08:02 1002178 /lib64/libnss_files-2.4.so
16299:20120822:073322.770 2b02561c8000-2b02562c7000 ---p 0000a000 08:02 1002178 /lib64/libnss_files-2.4.so
16299:20120822:073322.770 2b02562c7000-2b02562c9000 rw-p 00009000 08:02 1002178 /lib64/libnss_files-2.4.so
16299:20120822:073322.770 2b02562c9000-2b0256400000 r-xp 00000000 08:02 1001927 /lib64/libc-2.4.so
16299:20120822:073322.770 2b0256400000-2b02564ff000 ---p 00137000 08:02 1001927 /lib64/libc-2.4.so
16299:20120822:073322.770 2b02564ff000-2b0256502000 r--p 00136000 08:02 1001927 /lib64/libc-2.4.so
16299:20120822:073322.770 2b0256502000-2b0256504000 rw-p 00139000 08:02 1001927 /lib64/libc-2.4.so
16299:20120822:073322.770 2b0256504000-2b0256509000 rw-p 2b0256504000 00:00 0
16299:20120822:073322.770 2b0256509000-2b0256524000 r-xp 00000000 08:02 1001985 /lib64/ld-2.4.so
16299:20120822:073322.770 2b0256524000-2b0256623000 ---p 0001b000 08:02 1001985 /lib64/ld-2.4.so
16299:20120822:073322.770 2b0256623000-2b0256625000 rw-p 0001a000 08:02 1001985 /lib64/ld-2.4.so
16299:20120822:073322.770 2b0256625000-2b0256725000 rw-p 2b0256625000 00:00 0
16299:20120822:073322.770 2b0256725000-2b025673f000 r--p 00000000 08:02 971449 /etc/ld.so.cache
16299:20120822:073322.770 2b025673f000-2b0256744000 r-xp 00000000 08:02 1001963 /lib64/libnss_winbind.so.2
16299:20120822:073322.770 2b0256744000-2b0256844000 ---p 00005000 08:02 1001963 /lib64/libnss_winbind.so.2
16299:20120822:073322.770 2b0256844000-2b0256845000 rw-p 00005000 08:02 1001963 /lib64/libnss_winbind.so.2
16299:20120822:073322.770 2b0256845000-2b025684a000 rw-p 2b0256845000 00:00 0
16299:20120822:073322.770 2b025684a000-2b025685e000 r-xp 00000000 08:02 1001953 /lib64/libpthread-2.4.so
16299:20120822:073322.770 2b025685e000-2b025695d000 ---p 00014000 08:02 1001953 /lib64/libpthread-2.4.so
16299:20120822:073322.770 2b025695d000-2b025695f000 rw-p 00013000 08:02 1001953 /lib64/libpthread-2.4.so
16299:20120822:073322.770 2b025695f000-2b0256964000 rw-p 2b025695f000 00:00 0
16299:20120822:073322.770 7fff7b267000-7fff7b283000 rw-p 7fff7b267000 00:00 0 [stack]
16299:20120822:073322.770 7fff7b3ff000-7fff7b400000 r-xp 7fff7b3ff000 00:00 0
16299:20120822:073322.770 ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vdso]
16299:20120822:073322.770 ================================
16299:20120822:073322.770 Please consider attaching a disassembly listing to your bug report.
16299:20120822:073322.770 This listing can be produced with, e.g., objdump -DSswx zabbix_agentd.
16299:20120822:073322.770 ================================
16295:20120822:073322.770 One child process died (PID:16299,exitcode/signal:255). Exiting ...
16295:20120822:073322.770 zbx_on_exit() called
16296:20120822:073322.770 Got signal [signal:15(SIGTERM),sender_pid:16295,sender_uid:1203,reason:0]. Exiting ...
16297:20120822:073322.770 Got signal [signal:15(SIGTERM),sender_pid:16295,sender_uid:1203,reason:0]. Exiting ...
16298:20120822:073322.770 Got signal [signal:15(SIGTERM),sender_pid:16295,sender_uid:1203,reason:0]. Exiting ...
16295:20120822:073324.773 Zabbix Agent stopped. Zabbix 2.0.2 (revision 29214).