[collectd] Modbus segfault

Matt Baker matt at sevenone.com
Thu Dec 15 16:02:39 CET 2011


I am trying to get collectd working with the modbus plugin but I am getting a segfault each time collectd runs:

Dec 16 01:20:55  vmunix: [1074386.330565] collectd[29149]: segfault at 20 ip b7e03bcc sp b6fa1270 error 4 in libmodbus.so.4.0.0[b7e02000+6000]

Using Collectd version 5.0.1 with libmodbus 2.9.2 (have also tried 2.9.4 & 3.0.1).  Running ldd on the modbus.so looks like it is picking up the libmodbus correctly:

# ldd modbus.so
	linux-gate.so.1 =>  (0xffffe000)
	libmodbus.so.4 => /usr/lib/libmodbus.so.4 (0xb7ee1000)
	libdl.so.2 => /lib/libdl.so.2 (0xb7edd000)
	libc.so.6 => /lib/libc.so.6 (0xb7d9f000)
	/lib/ld-linux.so.2 (0xb7ef4000)

Config for the plugin in the collectd.conf file is just a minor modification of the documented example:

<Plugin modbus>
 <Data "voltage-input-1">
   RegisterBase 0
   RegisterType float
   Type voltage
   Instance "input-1"
 <Data "voltage-input-2">
   RegisterBase 2
   RegisterType float
   Type voltage
   Instance "input-2"
 <Host "">
  Address ""
  <Slave 1>
	Instance "power-supply"
	Collect  "voltage-input-1"

Just wondering if anyone has managed to get modbus support working with the latest version?


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