kern/163089: Duplicate free in the error return for mld_v2_encap_report in mld6.c

[Herbie Robinson]

>Number:         163089
>Category:       kern
>Synopsis:       Duplicate free in the error return for mld_v2_encap_report in mld6.c
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Dec 06 03:20:09 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Herbie Robinson
>Release:        8
>Organization:
Stratus Technologies
>Environment:
This is a port of the IPv6 code to a non-BSD operating system.  I [think] I have checked the latest CVS and the problem is still there.
>Description:
All of this is in src/sys/netinet6/mld6.c

The call code is:

		m0 = mld_v2_encap_report(ifp, m);
		if (m0 == NULL) {
			CTR2(KTR_MLD, "%s: dropped %p", __func__, m);
			m_freem(m);

The function mld_v2_encap_report consumes the mbuf in all cases (normal and error return); so, this is duplicate.  I haven't been working with the code long enough to know whether the coding philosophy would be to delete the free from the caller or the subroutine.  I would be inclined to remove the duplicate free from the caller...

I left the priority as low because memory allocation failures are rare these days... 

>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: