svn commit: r357149 - head/sys/fs/nfsserver

[Rick Macklem]

Author: rmacklem
Date: Sun Jan 26 17:59:05 2020
New Revision: 357149
URL: https://svnweb.freebsd.org/changeset/base/357149

Log:
  Fix a crash in the NFSv4 server.
  
  The PR reported a crash that occurred when a file was removed while
  client(s) were actively doing lock operations on it.
  Since nfsvno_getvp() will return NULL when the file does not exist,
  the bug was obvious and easy to fix via this patch. It is a little
  surprising that this wasn't found sooner, but I guess the above
  case rarely occurs.
  
  Tested by:	iron.udjin at gmail.com
  PR:		242768
  Reported by:	iron.udjin at gmail.com
  MFC after:	2 weeks

Modified:
  head/sys/fs/nfsserver/nfs_nfsdstate.c

Modified: head/sys/fs/nfsserver/nfs_nfsdstate.c
==============================================================================
--- head/sys/fs/nfsserver/nfs_nfsdstate.c	Sun Jan 26 17:22:05 2020	(r357148)
+++ head/sys/fs/nfsserver/nfs_nfsdstate.c	Sun Jan 26 17:59:05 2020	(r357149)
@@ -1554,7 +1554,8 @@ nfsrv_freeallnfslocks(struct nfsstate *stp, vnode_t vp
 				tvp = NULL;
 			else if (vp == NULL && cansleep != 0) {
 				tvp = nfsvno_getvp(&lfp->lf_fh);
-				NFSVOPUNLOCK(tvp);
+				if (tvp != NULL)
+					NFSVOPUNLOCK(tvp);
 			} else
 				tvp = vp;
 			gottvp = 1;