Accessing 'reg.write_index' directly triggers a -Waddress-of-packed-member warning due to potential unaligned pointer access:
perf_test.c:239:38: warning: taking address of packed member 'write_index' of class or structure 'user_reg' may result in an unaligned pointer value [-Waddress-of-packed-member] 239 | ASSERT_NE(-1, write(self->data_fd, ®.write_index, | ^~~~~~~~~~~~~~~
Since write(2) works with any alignment. Casting '®.write_index' explicitly to 'void *' to suppress this warning.
Signed-off-by: Ankit Khushwaha ankitkhushwaha.linux@gmail.com --- Changelog: v2: - typecast '®.write_index' to 'void *' & remove use of memcpy as suggested by Andrew.
v1: https://lore.kernel.org/linux-kselftest/20251027113439.36059-1-ankitkhushwah...
--- tools/testing/selftests/user_events/perf_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/user_events/perf_test.c b/tools/testing/selftests/user_events/perf_test.c index 201459d8094d..cafec0e52eb3 100644 --- a/tools/testing/selftests/user_events/perf_test.c +++ b/tools/testing/selftests/user_events/perf_test.c @@ -236,7 +236,7 @@ TEST_F(user, perf_empty_events) { ASSERT_EQ(1 << reg.enable_bit, self->check);
/* Ensure write shows up at correct offset */ - ASSERT_NE(-1, write(self->data_fd, ®.write_index, + ASSERT_NE(-1, write(self->data_fd, (void *)®.write_index, sizeof(reg.write_index))); val = (void *)(((char *)perf_page) + perf_page->data_offset); ASSERT_EQ(PERF_RECORD_SAMPLE, *val); -- 2.51.0