> -----Original Message----- > From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > Sent: Tuesday, June 2, 2020 11:47 AM > To: Kaneda, Erik <erik.kaneda@xxxxxxxxx> > Cc: Moore, Robert <robert.moore@xxxxxxxxx>; Wysocki, Rafael J > <rafael.j.wysocki@xxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>; Ard > Biesheuvel <ardb@xxxxxxxxxx>; dvyukov@xxxxxxxxxx; glider@xxxxxxxxxx; > guohanjun@xxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; lorenzo.pieralisi@xxxxxxx; > mark.rutland@xxxxxxx; pcc@xxxxxxxxxx; rjw@xxxxxxxxxxxxx; > will@xxxxxxxxxx; stable@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > devel@xxxxxxxxxx > Subject: Re: [PATCH] ACPICA: fix UBSAN warning using __builtin_offsetof > > 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.. > Hi, > 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 Why not use your host's stddef.h? > `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? Yes, the idea is to define ACPI_OFFSET in a way that you want so that we don't touch the uses below. Erik > > $ 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
