Re: [PATCH v2] ACPICA: Replace fake flexible arrays with flexible array members

[Guenter Roeck <linux@roeck-us.net>]

Hi,

On Fri, Jan 27, 2023 at 11:16:25AM -0800, Kees Cook wrote:
> One-element arrays (and multi-element arrays being treated as
> dynamically sized) are deprecated[1] and are being replaced with
> flexible array members in support of the ongoing efforts to tighten the
> FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
> with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.
> 
> Replace one-element array with flexible-array member in struct
> acpi_resource_extended_irq. Replace 4-byte fixed-size array with 4-byte
> padding in a union with a flexible-array member in struct
> acpi_pci_routing_table.
> 
> This results in no differences in binary output.
> 
> Link: https://github.com/acpica/acpica/pull/813
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch results in boot failures of 32-bit images.
Reverting it fixes the problem.

On the failing boot tests, I see messages such as

ACPI: \_SB_.GSIA: Enabled at IRQ 117440528
ERROR: Unable to locate IOAPIC for GSI 117440528
ahci 0000:00:1f.2: PCI INT A: failed to register GSI

ACPI: \_SB_.GSIG: Enabled at IRQ 117440534
ERROR: Unable to locate IOAPIC for GSI 117440534
8139cp 0000:00:02.0: PCI INT A: failed to register GSI

Given that 117440534 == 0x7000016, that looks quite suspicious.
Indeed, after reverting this patch, the messages are different.

ACPI: \_SB_.GSIA: Enabled at IRQ 16
ahci 0000:00:1f.2: AHCI 0001.0000 32 slots 6 ports 1.5 Gbps 0x3f impl SATA mode

ACPI: \_SB_.GSIG: Enabled at IRQ 22
8139cp 0000:00:02.0 eth0: RTL-8139C+ at 0xd0804000, 52:54:00:12:34:56, IRQ 22

Guenter