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

[Wysocki, Rafael J]

On 2/13/2023 1:35 AM, Guenter Roeck wrote:
> 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@xxxxxxxxxxxx>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> 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

Thanks for the report, I have reverted this commit from my linux-next 
branch and will not include it into my 6.3-rc1 pull requests at all.

Thanks!