svn commit: r306559 - head/sys/netinet

[Rick Macklem]

Author: rmacklem
Date: Sat Oct  1 19:39:09 2016
New Revision: 306559
URL: https://svnweb.freebsd.org/changeset/base/306559

Log:
  r297225 broke udp_output() for the case where the "addr" argument
  is NULL and the function jumps to the "release:" label.
  For this case, the "inp" was write locked, but the code attempted to
  read unlock it. This patch fixes the problem.
  This case could occur for NFS over UDP mounts, where the server was
  down for a few minutes under certain circumstances.
  
  Reported by:	bde
  Tested by:	bde
  Reviewed by:	gnn
  MFC after:	2 weeks

Modified:
  head/sys/netinet/udp_usrreq.c

Modified: head/sys/netinet/udp_usrreq.c
==============================================================================
--- head/sys/netinet/udp_usrreq.c	Sat Oct  1 19:30:28 2016	(r306558)
+++ head/sys/netinet/udp_usrreq.c	Sat Oct  1 19:39:09 2016	(r306559)
@@ -1567,12 +1567,18 @@ udp_output(struct inpcb *inp, struct mbu
 
 release:
 	if (unlock_udbinfo == UH_WLOCKED) {
+		KASSERT(unlock_inp == UH_WLOCKED,
+		    ("%s: excl udbinfo lock, shared inp lock", __func__));
 		INP_HASH_WUNLOCK(pcbinfo);
 		INP_WUNLOCK(inp);
 	} else if (unlock_udbinfo == UH_RLOCKED) {
+		KASSERT(unlock_inp == UH_RLOCKED,
+		    ("%s: shared udbinfo lock, excl inp lock", __func__));
 		INP_HASH_RUNLOCK(pcbinfo);
 		INP_RUNLOCK(inp);
-	} else
+	} else if (unlock_inp == UH_WLOCKED)
+		INP_WUNLOCK(inp);
+	else
 		INP_RUNLOCK(inp);
 	m_freem(m);
 	return (error);