Commit c7b607fa authored by Colin Ian King's avatar Colin Ian King Committed by Shuah Khan
Browse files

selftests/resctrl: Fix null pointer dereference on open failed 



Currently if opening /dev/null fails to open then file pointer fp
is null and further access to fp via fprintf will cause a null
pointer dereference. Fix this by returning a negative error value
when a null fp is detected.

Detected using cppcheck static analysis:
tools/testing/selftests/resctrl/fill_buf.c:124:6: note: Assuming
that condition '!fp' is not redundant
 if (!fp)
     ^
tools/testing/selftests/resctrl/fill_buf.c:126:10: note: Null
pointer dereference
 fprintf(fp, "Sum: %d ", ret);

Fixes: a2561b12 ("selftests/resctrl: Add built in benchmark")
Signed-off-by: default avatarColin Ian King <colin.i.king@gmail.com>
Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
parent 68c48449

tools/testing/selftests/resctrl/fill_buf.c

+3 −1
Original line number Diff line number Diff line
@@ -121,8 +121,10 @@ static int fill_cache_read(unsigned char *start_ptr, unsigned char *end_ptr, 


	/* Consume read result so that reading memory is not optimized out. */

	fp = fopen("/dev/null", "w");

	if (!fp)

	if (!fp) {

		perror("Unable to write to /dev/null");

		return -1;

	}

	fprintf(fp, "Sum: %d ", ret);

	fclose(fp);