diff --git a/SOURCES/rhbz1731333.patch b/SOURCES/rhbz1731333.patch
new file mode 100644
index 0000000..ce4ec4c
--- /dev/null
+++ b/SOURCES/rhbz1731333.patch
@@ -0,0 +1,48 @@
+commit 0c68adcd91cc40e825cfa5a7def29de4ac76b1f1
+Author: Frank Ch. Eigler <fche@redhat.com>
+Date:   Thu Aug 29 18:18:59 2019 -0400
+
+    rhbz1731333: nfsd.proc.write, tolerate awol 'vlen'
+    
+    This variable has disappeared from the kernel via commit
+    8154ef2776aa512a3eaa0e7db030dc4803354d61.  Substitute a 0.
+
+diff --git a/tapset/linux/nfsd.stp b/tapset/linux/nfsd.stp
+index aa04f24..5a77f4e 100644
+--- a/tapset/linux/nfsd.stp
++++ b/tapset/linux/nfsd.stp
+@@ -638,14 +638,14 @@ probe nfsd.proc2.write = kernel.function("nfsd_proc_write") !,
+ 		count = @nfsd2_writeargs($rqstp->rq_argp)->len
+ 		offset = @nfsd2_writeargs($rqstp->rq_argp)->offset 
+ 		vec = $rqstp->rq_vec
+-		vlen = @nfsd2_writeargs($rqstp->rq_argp)->vlen
++		vlen = @choose_defined(@nfsd2_writeargs($rqstp->rq_argp)->vlen, 0)
+ 	}
+ 	else {
+ 		fh = & @nfsd2_writeargs($argp)->fh
+ 		count = $argp->len
+ 		offset = $argp->offset 
+ 		vec = @choose_defined($rqstp->rq_vec, $argp->vec)
+-		vlen = $argp->vlen
++		vlen = @choose_defined($argp->vlen, 0)
+ 	}
+ 
+ 	stable = 1			# hardcoded in nfsd_proc_write()
+@@ -691,7 +691,7 @@ probe nfsd.proc3.write = kernel.function("nfsd3_proc_write") !,
+ 		count = @nfsd3_writeargs($rqstp->rq_argp)->count 
+ 		offset = @nfsd3_writeargs($rqstp->rq_argp)->offset 
+ 		vec = $rqstp->rq_vec
+-		vlen = @nfsd3_writeargs($rqstp->rq_argp)->vlen
++		vlen = @choose_defined(@nfsd3_writeargs($rqstp->rq_argp)->vlen, 0)
+ 		stable = @nfsd3_writeargs($rqstp->rq_argp)->stable
+ 	}
+ 	else {
+@@ -699,7 +699,7 @@ probe nfsd.proc3.write = kernel.function("nfsd3_proc_write") !,
+ 		count = $argp->count 
+ 		offset = $argp->offset 
+ 		vec = @choose_defined($rqstp->rq_vec, $argp->vec)
+-		vlen = $argp->vlen
++		vlen = @choose_defined($argp->vlen, 0)
+ 		stable = $argp->stable
+ 	}
+ 
diff --git a/SPECS/systemtap.spec b/SPECS/systemtap.spec
index 47f86e8..98e305b 100644
--- a/SPECS/systemtap.spec
+++ b/SPECS/systemtap.spec
@@ -88,7 +88,7 @@
 
 Name: systemtap
 Version: 4.0
-Release: 9%{?release_override}%{?dist}
+Release: 10%{?release_override}%{?dist}
 # for version, see also configure.ac
 
 
@@ -164,6 +164,7 @@ Patch36: rhbz1657857.patch
 Patch37: rhbz1657909.patch
 Patch50: bpf-unwarn.patch
 Patch51: stapbpf-kmsg.patch
+Patch52: rhbz1731333.patch
 
 # Build*
 BuildRequires: gcc-c++
@@ -616,6 +617,7 @@ cd ..
 %patch37 -p1
 %patch50 -p1
 %patch51 -p1
+%patch52 -p1
 
 %build
 
@@ -1359,6 +1361,9 @@ done
 
 # PRERELEASE
 %changelog
+* Tue Sep 03 2019 Frank Ch. Eigler <fche@elastic.org> - 4.0-10
+- rhbz1731333: nfsd.proc.write loss of vlen
+
 * Wed Apr 03 2019 Frank Ch. Eigler <fche@elastic.org> - 4.0-9
 - Backport stapbpf /dev/ksmg-related patches.