diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 9b0912a01777..31e1ff887e4b 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -55,6 +55,8 @@
 #include <setjmp.h>
 #include <stdbool.h>
 #include <assert.h>
+#include <inttypes.h>
+#include <stdint.h>
 
 #include "../kselftest.h"
 
@@ -135,6 +137,12 @@ static void usage(void)
 	exit(1);
 }
 
+static void uffd_error(const char *message, __s64 code)
+{
+	fprintf(stderr, "%s: %" PRId64 "\n", message, (int64_t)code);
+	exit(1);
+}
+
 static void uffd_stats_reset(struct uffd_stats *uffd_stats,
 			     unsigned long n_cpus)
 {
@@ -331,7 +339,7 @@ static int my_bcmp(char *str1, char *str2, size_t n)
 
 static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
 {
-	struct uffdio_writeprotect prms = { 0 };
+	struct uffdio_writeprotect prms;
 
 	/* Write protection page faults */
 	prms.range.start = start;
@@ -340,7 +348,8 @@ static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
 	prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0;
 
 	if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms)) {
-		fprintf(stderr, "clear WP failed for address 0x%Lx\n", start);
+		fprintf(stderr, "clear WP failed for address 0x%" PRIx64 "\n",
+			(uint64_t)start);
 		exit(1);
 	}
 }
@@ -474,14 +483,11 @@ static void retry_copy_page(int ufd, struct uffdio_copy *uffdio_copy,
 	if (ioctl(ufd, UFFDIO_COPY, uffdio_copy)) {
 		/* real retval in ufdio_copy.copy */
 		if (uffdio_copy->copy != -EEXIST) {
-			fprintf(stderr, "UFFDIO_COPY retry error %Ld\n",
-				uffdio_copy->copy);
-			exit(1);
+			uffd_error("UFFDIO_COPY retry error",
+				   uffdio_copy->copy);
 		}
-	} else {
-		fprintf(stderr,	"UFFDIO_COPY retry unexpected %Ld\n",
-			uffdio_copy->copy); exit(1);
-	}
+	} else
+		uffd_error("UFFDIO_COPY retry unexpected", uffdio_copy->copy);
 }
 
 static int __copy_page(int ufd, unsigned long offset, bool retry)
@@ -502,15 +508,11 @@ static int __copy_page(int ufd, unsigned long offset, bool retry)
 	uffdio_copy.copy = 0;
 	if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
 		/* real retval in ufdio_copy.copy */
-		if (uffdio_copy.copy != -EEXIST) {
-			fprintf(stderr, "UFFDIO_COPY error %Ld\n",
-				uffdio_copy.copy);
-			exit(1);
-		}
-	} else if (uffdio_copy.copy != page_size) {
-		fprintf(stderr, "UFFDIO_COPY unexpected copy %Ld\n",
-			uffdio_copy.copy); exit(1);
-	} else {
+		if (uffdio_copy.copy != -EEXIST)
+			uffd_error("UFFDIO_COPY error", uffdio_copy.copy);
+	} else if (uffdio_copy.copy != page_size)
+		uffd_error("UFFDIO_COPY unexpected copy", uffdio_copy.copy);
+	else {
 		if (test_uffdio_copy_eexist && retry) {
 			test_uffdio_copy_eexist = false;
 			retry_copy_page(ufd, &uffdio_copy, offset);
@@ -788,7 +790,8 @@ static int userfaultfd_open(int features)
 		return 1;
 	}
 	if (uffdio_api.api != UFFD_API) {
-		fprintf(stderr, "UFFDIO_API error %Lu\n", uffdio_api.api);
+		fprintf(stderr, "UFFDIO_API error: %" PRIu64 "\n",
+			(uint64_t)uffdio_api.api);
 		return 1;
 	}
 
@@ -950,13 +953,12 @@ static void retry_uffdio_zeropage(int ufd,
 				     offset);
 	if (ioctl(ufd, UFFDIO_ZEROPAGE, uffdio_zeropage)) {
 		if (uffdio_zeropage->zeropage != -EEXIST) {
-			fprintf(stderr, "UFFDIO_ZEROPAGE retry error %Ld\n",
-				uffdio_zeropage->zeropage);
-			exit(1);
+			uffd_error("UFFDIO_ZEROPAGE retry error",
+				   uffdio_zeropage->zeropage);
 		}
 	} else {
-		fprintf(stderr, "UFFDIO_ZEROPAGE retry unexpected %Ld\n",
-			uffdio_zeropage->zeropage); exit(1);
+		uffd_error("UFFDIO_ZEROPAGE retry unexpected",
+			   uffdio_zeropage->zeropage);
 	}
 }
 
@@ -979,26 +981,20 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
 	if (ret) {
 		/* real retval in ufdio_zeropage.zeropage */
 		if (has_zeropage) {
-			if (uffdio_zeropage.zeropage == -EEXIST) {
-				fprintf(stderr, "UFFDIO_ZEROPAGE -EEXIST\n");
-				exit(1);
-			} else {
-				fprintf(stderr, "UFFDIO_ZEROPAGE error %Ld\n",
-					uffdio_zeropage.zeropage);
-				exit(1);
-			}
+			uffd_error(uffdio_zeropage.zeropage == -EEXIST ?
+						 "UFFDIO_ZEROPAGE -EEXIST" :
+						 "UFFDIO_ZEROPAGE error",
+				   uffdio_zeropage.zeropage);
 		} else {
 			if (uffdio_zeropage.zeropage != -EINVAL) {
-				fprintf(stderr,
-					"UFFDIO_ZEROPAGE not -EINVAL %Ld\n",
-					uffdio_zeropage.zeropage);
-				exit(1);
+				uffd_error("UFFDIO_ZEROPAGE not -EINVAL",
+					   uffdio_zeropage.zeropage);
 			}
 		}
 	} else if (has_zeropage) {
 		if (uffdio_zeropage.zeropage != page_size) {
-			fprintf(stderr, "UFFDIO_ZEROPAGE unexpected %Ld\n",
-				uffdio_zeropage.zeropage); exit(1);
+			uffd_error("UFFDIO_ZEROPAGE unexpected",
+				   uffdio_zeropage.zeropage);
 		} else {
 			if (test_uffdio_zeropage_eexist && retry) {
 				test_uffdio_zeropage_eexist = false;
@@ -1008,9 +1004,8 @@ static int __uffdio_zeropage(int ufd, unsigned long offset, bool retry)
 			return 1;
 		}
 	} else {
-		fprintf(stderr,
-			"UFFDIO_ZEROPAGE succeeded %Ld\n",
-			uffdio_zeropage.zeropage); exit(1);
+		uffd_error("UFFDIO_ZEROPAGE succeeded",
+			   uffdio_zeropage.zeropage);
 	}
 
 	return 0;
