From 216158f063fe24fb003bd7da0cd92cd6e2c4d48b Mon Sep 17 00:00:00 2001 From: Ankit Khushwaha Date: Thu, 6 Nov 2025 15:25:32 +0530 Subject: [PATCH] selftests/user_events: fix type cast for write_index packed member in perf_test 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. Link: https://lkml.kernel.org/r/20251106095532.15185-1-ankitkhushwaha.linux@gmail.com Fixes: 42187bdc3ca4 ("selftests/user_events: Add perf self-test for empty arguments events") Signed-off-by: Ankit Khushwaha Cc: Beau Belgrave Cc: "Masami Hiramatsu (Google)" Cc: Steven Rostedt Cc: sunliming Cc: Wei Yang Cc: Shuah Khan Cc: Signed-off-by: Andrew Morton --- 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 5288e768b207a..68625362add28 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); -- 2.47.3