On 20. 6. 10., Kaneda, Erik wrote: > +JKim (for FreeBSD's perspective) > >> -----Original Message----- >> From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> >> Sent: Monday, June 1, 2020 4:18 PM >> To: Moore, Robert <robert.moore@xxxxxxxxx>; Kaneda, Erik >> <erik.kaneda@xxxxxxxxx>; Wysocki, Rafael J <rafael.j.wysocki@xxxxxxxxx>; >> Len Brown <lenb@xxxxxxxxxx> >> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>; dvyukov@xxxxxxxxxx; >> glider@xxxxxxxxxx; guohanjun@xxxxxxxxxx; linux-arm- >> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; >> lorenzo.pieralisi@xxxxxxx; mark.rutland@xxxxxxx; >> ndesaulniers@xxxxxxxxxx; pcc@xxxxxxxxxx; rjw@xxxxxxxxxxxxx; >> will@xxxxxxxxxx; stable@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; >> devel@xxxxxxxxxx >> Subject: [PATCH] ACPICA: fix UBSAN warning using __builtin_offsetof >> >> 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 >> > Hi, > >> Looks like the emulated offsetof macro ACPI_OFFSET is causing these. We >> can avoid this by using the compiler builtin, __builtin_offsetof. >> > This doesn't really fly because __builtin_offsetof is a compiler extension. > > It looks like a lot of stddef.h files do this: > > #define offsetof(a,b) __builtin_offset(a,b) > > So does anyone have objections to ACPI_OFFSET being defined to offsetof()? > > This will allow a host OS project project to use their own definitions of offsetof in place of ACPICA's. > If they don't have a definition for offsetof, we can supply the old one as a fallback. > > Here's a patch: > > --- a/include/acpi/actypes.h > +++ b/include/acpi/actypes.h > @@ -504,11 +504,17 @@ typedef u64 acpi_integer; > #define ACPI_SUB_PTR(t, a, b) ACPI_CAST_PTR (t, (ACPI_CAST_PTR (u8, (a)) - (acpi_size)(b))) > #define ACPI_PTR_DIFF(a, b) ((acpi_size) (ACPI_CAST_PTR (u8, (a)) - ACPI_CAST_PTR (u8, (b)))) > > +/* Use an existing definiton for offsetof */ > + > +#ifndef offsetof > +#define offsetof(d,f) ACPI_PTR_DIFF (&(((d *) 0)->f), (void *) 0) > +#endif > + > /* Pointer/Integer type conversions */ > > #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) offsetof (d,f) > #define ACPI_PHYSADDR_TO_PTR(i) ACPI_TO_POINTER(i) > #define ACPI_PTR_TO_PHYSADDR(i) ACPI_TO_INTEGER(i) LGTM. Jung-uk Kim >> 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: stable@xxxxxxxxxxxxxxx >> Reported-by: Will Deacon <will@xxxxxxxxxx> >> Suggested-by: Ard Biesheuvel <ardb@xxxxxxxxxx> >> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> >> --- >> 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 >
