svn commit: r291040 - head/sys/netinet

[Conrad E. Meyer]

Author: cem
Date: Wed Nov 18 23:53:13 2015
New Revision: 291040
URL: https://svnweb.freebsd.org/changeset/base/291040

Log:
  in_getmulti: Fix recursion on if_addr_lock on malloc failure
  
  When the M_NOWAIT allocation fails, we recurse the if_addr_lock trying
  to clean up.  Reorder the cleanup after dropping the if_addr_lock.  The
  obvious race is already possible between if_addmulti and IF_ADDR_WLOCK
  above, so it must be ok.
  
  Submitted by:	Ryan Libby <rlibby at gmail.com>
  Reviewed by:	jhb
  Found with:	M_NOWAIT failure injection testing
  Sponsored by:	EMC / Isilon Storage Division
  Differential Revision:	https://reviews.freebsd.org/D4138

Modified:
  head/sys/netinet/in_mcast.c

Modified: head/sys/netinet/in_mcast.c
==============================================================================
--- head/sys/netinet/in_mcast.c	Wed Nov 18 23:45:09 2015	(r291039)
+++ head/sys/netinet/in_mcast.c	Wed Nov 18 23:53:13 2015	(r291040)
@@ -515,8 +515,8 @@ in_getmulti(struct ifnet *ifp, const str
 	 */
 	inm = malloc(sizeof(*inm), M_IPMADDR, M_NOWAIT | M_ZERO);
 	if (inm == NULL) {
-		if_delmulti_ifma(ifma);
 		IF_ADDR_WUNLOCK(ifp);
+		if_delmulti_ifma(ifma);
 		return (ENOMEM);
 	}
 	inm->inm_addr = *group;