-----Original Message-----
From: Nick Desaulniers <ndesaulniers@google.com>
Sent: Tuesday, June 2, 2020 11:47 AM
To: Kaneda, Erik <redacted>
Cc: Moore, Robert <redacted>; Wysocki, Rafael J
[off-list ref]; Len Brown [off-list ref]; Ard
Biesheuvel [off-list ref]; dvyukov@google.com; glider@google.com;
guohanjun@huawei.com; linux-arm-kernel@lists.infradead.org; linux-
kernel@vger.kernel.org; lorenzo.pieralisi@arm.com;
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will@kernel.org; stable@vger.kernel.org; linux-acpi@vger.kernel.org;
devel@acpica.org
Subject: Re: [PATCH] ACPICA: fix UBSAN warning using __builtin_offsetof
On Mon, Jun 1, 2020 at 5:03 PM Kaneda, Erik [off-list ref]
wrote:
quoted
Hi,
quoted
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
quoted
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
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