On Mon, Jun 08, 2020 at 01:38:17PM -0700, Nick Desaulniers wrote: > Will reported a UBSAN warning: > > UBSAN: null-ptr-deref in arch/arm64/kernel/smp.c:596:6 > member access within null pointer of type 'struct acpi_madt_generic_interrupt' > CPU: 0 PID: 0 Comm: swapper Not tainted 5.7.0-rc6-00124-g96bc42ff0a82 #1 > Call trace: > dump_backtrace+0x0/0x384 > show_stack+0x28/0x38 > dump_stack+0xec/0x174 > handle_null_ptr_deref+0x134/0x174 > __ubsan_handle_type_mismatch_v1+0x84/0xa4 > acpi_parse_gic_cpu_interface+0x60/0xe8 > acpi_parse_entries_array+0x288/0x498 > acpi_table_parse_entries_array+0x178/0x1b4 > acpi_table_parse_madt+0xa4/0x110 > acpi_parse_and_init_cpus+0x38/0x100 > smp_init_cpus+0x74/0x258 > setup_arch+0x350/0x3ec > start_kernel+0x98/0x6f4 > > This is from the use of the ACPI_OFFSET in > arch/arm64/include/asm/acpi.h. Replace its use with offsetof from > include/linux/stddef.h which should implement the same logic using > __builtin_offsetof, so that UBSAN wont warn. > > Link: https://lore.kernel.org/lkml/20200521100952.GA5360@willie-the-truck/ > Cc: stable@xxxxxxxxxxxxxxx > Reported-by: Will Deacon <will@xxxxxxxxxx> > Suggested-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > Changes V1 -> V2: > * Just fix one of the two warnings, specific to arm64. > * Put warning in commit message. > > arch/arm64/include/asm/acpi.h | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index b263e239cb59..a45366c3909b 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -12,6 +12,7 @@ > #include <linux/efi.h> > #include <linux/memblock.h> > #include <linux/psci.h> > +#include <linux/stddef.h> > > #include <asm/cputype.h> > #include <asm/io.h> > @@ -31,14 +32,14 @@ > * is therefore used to delimit the MADT GICC structure minimum length > * appropriately. > */ > -#define ACPI_MADT_GICC_MIN_LENGTH ACPI_OFFSET( \ > +#define ACPI_MADT_GICC_MIN_LENGTH offsetof( \ > struct acpi_madt_generic_interrupt, efficiency_class) > > #define BAD_MADT_GICC_ENTRY(entry, end) \ > (!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \ > (unsigned long)(entry) + (entry)->header.length > (end)) > > -#define ACPI_MADT_GICC_SPE (ACPI_OFFSET(struct acpi_madt_generic_interrupt, \ > +#define ACPI_MADT_GICC_SPE (offsetof(struct acpi_madt_generic_interrupt, \ > spe_interrupt) + sizeof(u16)) > > /* Basic configuration for ACPI */ > -- > 2.27.0.278.ge193c7cf3a9-goog >
