pkg/50995: sigsegv in recv()

[prlw1%cam.ac.uk@localhost]

>Number:         50995
>Category:       pkg
>Synopsis:       sigsegv in recv()
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Mar 23 17:10:00 +0000 2016
>Originator:     Patrick Welche
>Release:        NetBSD-7/amd64
>Organization:
>Environment:
>Description:
Running pkgsrc dansguardian 2.12.0.3nb4 on a busy NetBSD-7/amd64 (both
original 7 kernel and most recent from 7 branch), dansguardian will run
fine for say a fortnight, then run through a patch of coredumps as a
result of a SIGSEGV. There is no apparent pattern. Could also coredump
on startup.

NetBSD-5/i386 does not exhibit the problem.

  http://www.netbsd.org/~sborrill/dansguardian/

contains the patches that were added to dansguardian to try to see
whether the issue was with the application or the recv() call.
BaseSocket.cc is the patched source file. The syslog line is not
reached. "dansguardian" is the 9.2M binary with symbols, dansguardian.core
one of the 43M core files. core file says:

Program terminated with signal SIGSEGV, Segmentation fault.
#0  BaseSocket::readFromSocket (this=0x7f7f00000001, 
    this@entry=0x7f7fffffd320, buff=buff@entry=0x7f7fffffd25e "", 
    len=len@entry=1, flags=flags@entry=0, timeout=timeout@entry=360, 
    check_first=check_first@entry=true, 
    honour_reloadconfig=honour_reloadconfig@entry=true) at BaseSocket.cpp:476

476                     rc = recv(sck, buff, cnt, flags);

Conjecture: another manifestation of the recvfrom returns EAGAIN loop problem.
>How-To-Repeat:

>Fix: