Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Tue, 22 Aug 2006 16:41:52 +0200

Hi Jeff, hi Eric,

a colleage of mine is trying to get EPICS running on RTEMS running on an

ARM v4t.

The system crashes with a alignment fault in in BSD network stack

function in_control() which gets a struct ifreq pointer. This pointer is

created in osiSockDiscoverBroadcastAddresses(), where you create an

array of such structures by calloc()ing 100 times the size of an struct

ifreq (line 87).

Then you step through the array. When you call socket_ioctl() to get the

broadcast address (line 177), that call causes the crash down in the BSD

stack, because at that point the pointer pifreq is not word-aligned.

We think that somehow within the array the single struct ifreq entries

are not word-aligned - which sounds not very likely looking at the ifreq

definition, or that your stepping algorithm in ifreqNext() (line 38 ff.)

returns a wrong address which is odd.

Any ideas?

What was the reason for using the ifreqNext() function instead of just

stepping with sizeof (struct ifreq)?

Clueless,
Ralph & Ralf

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System