# \[PATCH\] ACPICA: fix UBSAN warning using \_\_builtin\_offsetof - From: Nick Desaulniers \ - Date: 2020-06-01 23:18:21 - List: linux-arm-kernel - Page: https://ratatoskr.run/linux-arm-kernel/2020/06/5986528 - Thread: https://ratatoskr.run/linux-arm-kernel/2020/05/5973580/t.md ```text 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. The non-kernel runtime of UBSAN would print: runtime error: member access within null pointer of type for this macro. Link: https://lore.kernel.org/lkml/20200521100952.GA5360@willie-the-truck/ Cc: Reported-by: Will Deacon Suggested-by: Ard Biesheuvel Signed-off-by: Nick Desaulniers --- include/acpi/actypes.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h index 4defed58ea33..04359c70b198 100644 --- a/include/acpi/actypes.h +++ b/include/acpi/actypes.h @@ -508,7 +508,7 @@ typedef u64 acpi_integer; #define ACPI_TO_POINTER(i) ACPI_CAST_PTR (void, (acpi_size) (i)) #define ACPI_TO_INTEGER(p) ACPI_PTR_DIFF (p, (void *) 0) -#define ACPI_OFFSET(d, f) ACPI_PTR_DIFF (&(((d *) 0)->f), (void *) 0) +#define ACPI_OFFSET(d, f) __builtin_offsetof(d, f) #define ACPI_PHYSADDR_TO_PTR(i) ACPI_TO_POINTER(i) #define ACPI_PTR_TO_PHYSADDR(i) ACPI_TO_INTEGER(i) -- 2.27.0.rc2.251.g90737beb825-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ```