From 575882a29b29cd7007627eb86ceb1fd8d2c43a11 Mon Sep 17 00:00:00 2001 From: Emanuele Rocca To: linux-kernel@vger.kernel.org Cc: linux-kselftest@vger.kernel.org, Clint George , Shuah Khan , Christian Brauner , Mark Brown Date: Fri, 20 Mar 2026 20:12:31 +0100 Subject: [PATCH] kselftest/coredump: reintroduce null pointer dereference Commit 673a55cc49da replaced the null pointer dereference used in crashing_child() with __builtin_trap to address the following LLVM warnings: coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference] coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile' All coredump tests expect crashing_child() to result in a SIGSEGV. However, the behavior of __builtin_trap is architecture-dependent. On x86 it yields SIGILL, on aarch64 SIGTRAP. Given that neither of those signals are SIGSEGV, both coredump_socket_test and coredump_socket_protocol_test are currently failing: get_pidfd_info: mask=0xd7, coredump_mask=0x5, coredump_signal=5 socket_coredump_signal_sigsegv: coredump_signal=5, expected SIGSEGV=11 Qualify the pointer with volatile instead of calling __builtin_trap to fix the tests. Signed-off-by: Emanuele Rocca --- tools/testing/selftests/coredump/coredump_test_helpers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/coredump/coredump_test_helpers.c b/tools/testing/selftests/coredump/coredump_test_helpers.c index 5c8adee63641..2c850e0b1b57 100644 --- a/tools/testing/selftests/coredump/coredump_test_helpers.c +++ b/tools/testing/selftests/coredump/coredump_test_helpers.c @@ -56,7 +56,7 @@ void crashing_child(void) pthread_create(&thread, NULL, do_nothing, NULL); /* crash on purpose */ - __builtin_trap(); + i = *(volatile int *)NULL; } int create_detached_tmpfs(void) -- 2.43.0