On Mon, Jun 1, 2020 at 5:03 PM Kaneda, Erik <erik.kaneda@xxxxxxxxx> wrote: > > > Hi, > > > Will reported UBSAN warnings: > > UBSAN: null-ptr-deref in drivers/acpi/acpica/tbfadt.c:459:37 > > UBSAN: null-ptr-deref in arch/arm64/kernel/smp.c:596:6 > > > > Looks like the emulated offsetof macro ACPI_OFFSET is causing these. We > > can avoid this by using the compiler builtin, __builtin_offsetof. > > I'll take a look at this tomorrow > > > > The non-kernel runtime of UBSAN would print: > > runtime error: member access within null pointer of type for this macro. > > actypes.h is owned by ACPICA so we typically do not allow compiler-specific > extensions because the code is intended to be compiled using the C99 standard > without compiler extensions. We could allow this sort of thing in a Linux-specific > header file like include/acpi/platform/aclinux.h but I'll take a look at the error as well.. If I'm not allowed to touch that header, it looks like I can include <linux/stddef.h> (rather than my host's <stddef.h>) to get a definition of `offsetof` thats implemented in terms of `__builtin_offsetof`. I should be able to use that to replace uses of ACPI_OFFSET. Are any of these off limits? $ grep -rn ACPI_OFFSET arch/arm64/include/asm/acpi.h:34:#define ACPI_MADT_GICC_MIN_LENGTH ACPI_OFFSET( \ arch/arm64/include/asm/acpi.h:41:#define ACPI_MADT_GICC_SPE (ACPI_OFFSET(struct acpi_madt_generic_interrupt, \ include/acpi/actbl.h:376:#define ACPI_FADT_OFFSET(f) (u16) ACPI_OFFSET (struct acpi_table_fadt, f) drivers/acpi/acpica/acresrc.h:84:#define ACPI_RS_OFFSET(f) (u8) ACPI_OFFSET (struct acpi_resource,f) drivers/acpi/acpica/acresrc.h:85:#define AML_OFFSET(f) (u8) ACPI_OFFSET (union aml_resource,f) drivers/acpi/acpica/acinterp.h:17:#define ACPI_EXD_OFFSET(f) (u8) ACPI_OFFSET (union acpi_operand_object,f) drivers/acpi/acpica/acinterp.h:18:#define ACPI_EXD_NSOFFSET(f) (u8) ACPI_OFFSET (struct acpi_namespace_node,f) drivers/acpi/acpica/rsdumpinfo.c:16:#define ACPI_RSD_OFFSET(f) (u8) ACPI_OFFSET (union acpi_resource_data,f) drivers/acpi/acpica/rsdumpinfo.c:17:#define ACPI_PRT_OFFSET(f) (u8) ACPI_OFFSET (struct acpi_pci_routing_table,f) -- Thanks, ~Nick Desaulniers
