Description of problem:
Dell PE1950 Server servicing as IPv6 TS stream convert to IPv4 TS stream, using VLC, have 450Mbps multicasat net flow in/out.
net-snmp snmpd service crash within servial days.

Crash gdb propmt:
Program received signal SIGFPE, Arithmetic exception.
0x00002aaaab37744a in var_hrproc (vp=0x7fffffffbf50,
    name=<value optimized out>, length=<value optimized out>,
    exact=<value optimized out>, var_len=0x7fffffffcb80,
    write_method=<value optimized out>) at host/hr_proc.c:183
183             long_return  = 100 - long_return;


(gdb) disassemble
Dump of assembler code for function var_hrproc:
0x00002aaaab3773a0 <var_hrproc+0>:      push   %rbp
......
0x00002aaaab377446 <var_hrproc+166>:    sub    0x20(%rcx),%rdi
0x00002aaaab37744a <var_hrproc+170>:    div    %rdi
0x00002aaaab37744d <var_hrproc+173>:    mov    $0x64,%edx
......

(gdb) info registers
rax            0x0      0
rbx            0x7fffffffcb80   140737488341888
rcx            0x2aaab4f0e180   46912668492160
rdx            0x0      0
rsi            0x2aaaab119170   46912502862192
rdi            0x0      0
rbp            0x7fffffffbf50   0x7fffffffbf50
rsp            0x7fffffffbee0   0x7fffffffbee0
......

It is certian that the SIGFPE was lead by a DIV ZERO.

Trace the code [net-snmp-5.4.2.1]
agent/mibgroup/host/hr_proc.c, Line 181 - 185
        long_return  = (cpu->idle_ticks  - cpu->history[0].idle_hist)*100;
        long_return /= (cpu->total_ticks - cpu->history[0].total_hist);
        long_return  = 100 - long_return;
        if (long_return < 0)
            long_return = 0;

Summary:
BUG1. I think the absence of ZERO check before div in hr_proc.c line 182 causes the SIGFPE crash.
BUG2. hr_proc.c line 184-185 no longer work as before as long_return is now a unsigned var.
Since version 5.4.2, var long_return's definition changed from [signed long] to [fsblkcnt_t], which is always a unsigned integer. So line 184-185 will no longer work correctly.
long_return define:
agent/snmp_vars.c:fsblkcnt_t            long_return;


Version-Release number of selected component (if applicable):
Name        : net-snmp                     Relocations: (not relocatable)
Version     : 5.4.2.1                           Vendor: Fedora Project
Release     : 3.fc10                        Build Date: Mon 16 Feb 2009 07:26:07 PM CST


How reproducible:
Background net-flow 450Mbps IPv6(in)/IPv4(out) multicast IPTV TS flow(transform by vlc).
Start /etc/init.d/snmpd service, it crash within serval days.

Steps to Reproduce:
1. Background net-flow 450Mbps IPv6(in)/IPv4(out) multicast IPTV TS flow(transform by vlc).
2. Start /etc/init.d/snmpd service, and wait for it crash with serval days
  
Actual results:
snmpd crash with servial days

Expected results:
snmpd continue work without SIGFPE crash

Additional info: