[153/155] selftests/vm: fix map_hugetlb length used for testing read and write

Commit Message

Andrew Morton April 2, 2020, 4:11 a.m. UTC

From: Christophe Leroy <[e-mail]>
Subject: selftests/vm: fix map_hugetlb length used for testing read and write

Commit fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page
size in map_hugetlb") added the possibility to change the size of memory
mapped for the test, but left the read and write test using the default
value.  This is unnoticed when mapping a length greater than the default
one, but segfaults otherwise.

Fix read_bytes() and write_bytes() by giving them the real length.

Also fix the call to munmap().

Link: http://lkml.kernel.org/r/9a404a13[e-mail]
Fixes: fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page size in map_hugetlb")
Signed-off-by: Christophe Leroy <[e-mail]>
Reviewed-by: Leonardo Bras <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 tools/testing/selftests/vm/map_hugetlb.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

Patch

--- a/tools/testing/selftests/vm/map_hugetlb.c~selftests-vm-fix-map_hugetlb-length-used-for-testing-read-and-write
+++ a/tools/testing/selftests/vm/map_hugetlb.c
@@ -45,20 +45,20 @@  static void check_bytes(char *addr)
 	printf("First hex is %x\n", *((unsigned int *)addr));
 }
 
-static void write_bytes(char *addr)
+static void write_bytes(char *addr, size_t length)
 {
 	unsigned long i;
 
-	for (i = 0; i < LENGTH; i++)
+	for (i = 0; i < length; i++)
 		*(addr + i) = (char)i;
 }
 
-static int read_bytes(char *addr)
+static int read_bytes(char *addr, size_t length)
 {
 	unsigned long i;
 
 	check_bytes(addr);
-	for (i = 0; i < LENGTH; i++)
+	for (i = 0; i < length; i++)
 		if (*(addr + i) != (char)i) {
 			printf("Mismatch at %lu\n", i);
 			return 1;
@@ -96,11 +96,11 @@  int main(int argc, char **argv)
 
 	printf("Returned address is %p\n", addr);
 	check_bytes(addr);
-	write_bytes(addr);
-	ret = read_bytes(addr);
+	write_bytes(addr, length);
+	ret = read_bytes(addr, length);
 
 	/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
-	if (munmap(addr, LENGTH)) {
+	if (munmap(addr, length)) {
 		perror("munmap");
 		exit(1);
 	}