From: Emanuele Rocca Date: Fri, 20 Mar 2026 19:46:43 +0000 (+0100) Subject: kselftest/coredump: reintroduce null pointer dereference X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3fc66a103395b4ae8d032dcda5621423d94902f6;p=thirdparty%2Fkernel%2Fstable.git 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 Link: https://patch.msgid.link/ab2kI0PI_Vk6bU88@NH27D9T0LF Reviewed-by: Mark Brown Signed-off-by: Christian Brauner --- diff --git a/tools/testing/selftests/coredump/coredump_test_helpers.c b/tools/testing/selftests/coredump/coredump_test_helpers.c index 5c8adee636414..2c850e0b1b57c 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)