RE: [PATCH 20/27] ACPICA: Tables: Fix invalid pointer accesses in acpi_tb_parse_root_table().

[Zheng, Lv]

Hi, Rafael

> From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi-owner@xxxxxxxxxxxxxxx] On Behalf Of Rafael J. Wysocki
> Sent: Monday, May 05, 2014 8:43 AM
> 
> On Saturday, May 03, 2014 08:59:14 AM Josh Boyer wrote:
> > On Tue, Apr 29, 2014 at 10:05 PM, Lv Zheng <lv.zheng@xxxxxxxxx> wrote:
> > > The commit of back porting Linux XSDT validation mechanism has introduced
> > > a regreession:
> > >   Commit: 671cc68dc61f029d44b43a681356078e02d8dab8
> > >   Subject: ACPICA: Back port and refine validation of the XSDT root table.
> > > There is a pointer still accessed after unmapping.
> > >
> > > This patch fixes this issue.  Lv Zheng.
> > >
> > > Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=73911
> > > Buglink: https://bugs.archlinux.org/task/39811
> > > Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
> > > Reported-and-tested-by: Bruce Chiarelli <mano155@xxxxxxxxx>
> > > Reported-and-tested-by: Spyros Stathopoulos <spystath@xxxxxxxxx>
> > > Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx>
> > > Cc: <stable@xxxxxxxxxxxxxxx> # 3.14.x: 671cc68: ACPICA: Back port and refine validation of the XSDT root table.
> >
> > This patch should get into 3.15-rcX soon.  It fixes a known regression
> > that prevents booting on machines with AMI firmware, and that is
> > present in 3.14 so we need it for stable as well.  Rafael?
> 
> Lv, is it safe to take this patch alone into 3.15-rc?

Yes, it's safe to only take this patch to be a regression fix.
I'm sorry for the regression I made in the bisected commit.

Thanks and best regards
-Lv

> 
> Rafael
> 
> 
> > > ---
> > >  drivers/acpi/acpica/tbutils.c |    7 +++++--
> > >  1 file changed, 5 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
> > > index 6c31d77..e1638ad 100644
> > > --- a/drivers/acpi/acpica/tbutils.c
> > > +++ b/drivers/acpi/acpica/tbutils.c
> > > @@ -355,6 +355,7 @@ acpi_status __init acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
> > >         u32 table_count;
> > >         struct acpi_table_header *table;
> > >         acpi_physical_address address;
> > > +       acpi_physical_address rsdt_address;
> > >         u32 length;
> > >         u8 *table_entry;
> > >         acpi_status status;
> > > @@ -383,11 +384,14 @@ acpi_status __init acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
> > >                  * as per the ACPI specification.
> > >                  */
> > >                 address = (acpi_physical_address) rsdp->xsdt_physical_address;
> > > +               rsdt_address =
> > > +                   (acpi_physical_address) rsdp->rsdt_physical_address;
> > >                 table_entry_size = ACPI_XSDT_ENTRY_SIZE;
> > >         } else {
> > >                 /* Root table is an RSDT (32-bit physical addresses) */
> > >
> > >                 address = (acpi_physical_address) rsdp->rsdt_physical_address;
> > > +               rsdt_address = address;
> > >                 table_entry_size = ACPI_RSDT_ENTRY_SIZE;
> > >         }
> > >
> > > @@ -410,8 +414,7 @@ acpi_status __init acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
> > >
> > >                         /* Fall back to the RSDT */
> > >
> > > -                       address =
> > > -                           (acpi_physical_address) rsdp->rsdt_physical_address;
> > > +                       address = rsdt_address;
> > >                         table_entry_size = ACPI_RSDT_ENTRY_SIZE;
> > >                 }
> > >         }
> > > --
> > > 1.7.10
> > >
> > > --
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> 
> --
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.
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