From: Rong Tao <rongtao@xxxxxxxx>
When testing overflow and overread, there is no need to keep unnecessary
compilation warnings, we should simply ignore them.
How to reproduce the problem:
$ make -C tools/testing/selftests/
gcc huge_count_read_write.c -o /home/sd/Git/linux/tools/testing/selftests/damon/huge_count_read_write
huge_count_read_write.c: In function ‘write_read_with_huge_count’:
huge_count_read_write.c:23:9: warning: ‘write’ reading 4294967295 bytes from a region of size 1 [-Wstringop-overread]
23 | write(filedesc, "", 0xfffffffful);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from huge_count_read_write.c:8:
/usr/include/unistd.h:378:16: note: in a call to function ‘write’ declared with attribute ‘access (read_only, 2, 3)’
378 | extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur
| ^~~~~
huge_count_read_write.c:25:15: warning: ‘read’ writing 4294967295 bytes into a region of size 25 overflows the destination [-Wstringop-overflow=]
25 | ret = read(filedesc, buf, 0xfffffffful);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
huge_count_read_write.c:14:14: note: destination object ‘buf’ of size 25
14 | char buf[25];
| ^~~
In file included from huge_count_read_write.c:8:
/usr/include/unistd.h:371:16: note: in a call to function ‘read’ declared with attribute ‘access (write_only, 2, 3)’
371 | extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur
| ^~~~
Signed-off-by: Rong Tao <rongtao@xxxxxxxx>
---
tools/testing/selftests/damon/huge_count_read_write.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/tools/testing/selftests/damon/huge_count_read_write.c b/tools/testing/selftests/damon/huge_count_read_write.c
index ad7a6b4cf338..8fbe276870e7 100644
--- a/tools/testing/selftests/damon/huge_count_read_write.c
+++ b/tools/testing/selftests/damon/huge_count_read_write.c
@@ -8,6 +8,11 @@
#include <unistd.h>
#include <stdio.h>
+#pragma GCC diagnostic push
+/* Ignore read(2) overflow and write(2) overread compile warnings */
+#pragma GCC diagnostic ignored "-Wstringop-overread"
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
+
void write_read_with_huge_count(char *file)
{
int filedesc = open(file, O_RDWR);
@@ -27,6 +32,8 @@ void write_read_with_huge_count(char *file)
close(filedesc);
}
+#pragma GCC diagnostic pop
+
int main(int argc, char *argv[])
{
if (argc != 2) {
--
2.31.1
