Re: [PATCH] ACPI: tables: x86: Reserve memory occupied by ACPI tables

[Rafael J. Wysocki]

On Wed, Mar 24, 2021 at 9:24 AM Mike Rapoport <rppt@xxxxxxxxxxxxx> wrote:
>
> On Tue, Mar 23, 2021 at 08:26:52PM +0100, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > The following problem has been reported by George Kennedy:
> >
> >  Since commit 7fef431be9c9 ("mm/page_alloc: place pages to tail
> >  in __free_pages_core()") the following use after free occurs
> >  intermittently when ACPI tables are accessed.
> >
> >  BUG: KASAN: use-after-free in ibft_init+0x134/0xc49
> >  Read of size 4 at addr ffff8880be453004 by task swapper/0/1
> >  CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc1-7a7fd0d #1
> >  Call Trace:
> >   dump_stack+0xf6/0x158
> >   print_address_description.constprop.9+0x41/0x60
> >   kasan_report.cold.14+0x7b/0xd4
> >   __asan_report_load_n_noabort+0xf/0x20
> >   ibft_init+0x134/0xc49
> >   do_one_initcall+0xc4/0x3e0
> >   kernel_init_freeable+0x5af/0x66b
> >   kernel_init+0x16/0x1d0
> >   ret_from_fork+0x22/0x30
> >
> >  ACPI tables mapped via kmap() do not have their mapped pages
> >  reserved and the pages can be "stolen" by the buddy allocator.
> >
> > Apparently, on the affected system, the ACPI table in question is
> > not located in "reserved" memory, like ACPI NVS or ACPI Data, that
> > will not be used by the buddy allocator, so the memory occupied by
> > that table has to be explicitly reserved to prevent the buddy
> > allocator from using it.
> >
> > In order to address this problem, rearrange the initialization of the
> > ACPI tables on x86 to locate the initial tables earlier and reserve
> > the memory occupied by them.
> >
> > The other architectures using ACPI should not be affected by this
> > change.
> >
> > Link: https://lore.kernel.org/linux-acpi/1614802160-29362-1-git-send-email-george.kennedy@xxxxxxxxxx/
> > Reported-by: George Kennedy <george.kennedy@xxxxxxxxxx>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> FWIW:
> Reviewed-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>

Thank you!

George, can you please try this patch on the affected system?

> > ---
> >  arch/x86/kernel/acpi/boot.c |   25 ++++++++++++-------------
> >  arch/x86/kernel/setup.c     |    8 +++-----
> >  drivers/acpi/tables.c       |   42 +++++++++++++++++++++++++++++++++++++++---
> >  include/linux/acpi.h        |    9 ++++++++-
> >  4 files changed, 62 insertions(+), 22 deletions(-)
> >
> > Index: linux-pm/arch/x86/kernel/acpi/boot.c
> > ===================================================================
> > --- linux-pm.orig/arch/x86/kernel/acpi/boot.c
> > +++ linux-pm/arch/x86/kernel/acpi/boot.c
> > @@ -1554,10 +1554,18 @@ void __init acpi_boot_table_init(void)
> >       /*
> >        * Initialize the ACPI boot-time table parser.
> >        */
> > -     if (acpi_table_init()) {
> > +     if (acpi_locate_initial_tables())
> >               disable_acpi();
> > -             return;
> > -     }
> > +     else
> > +             acpi_reserve_initial_tables();
> > +}
> > +
> > +int __init early_acpi_boot_init(void)
> > +{
> > +     if (acpi_disabled)
> > +             return 1;
> > +
> > +     acpi_table_init_complete();
> >
> >       acpi_table_parse(ACPI_SIG_BOOT, acpi_parse_sbf);
> >
> > @@ -1570,18 +1578,9 @@ void __init acpi_boot_table_init(void)
> >               } else {
> >                       printk(KERN_WARNING PREFIX "Disabling ACPI support\n");
> >                       disable_acpi();
> > -                     return;
> > +                     return 1;
> >               }
> >       }
> > -}
> > -
> > -int __init early_acpi_boot_init(void)
> > -{
> > -     /*
> > -      * If acpi_disabled, bail out
> > -      */
> > -     if (acpi_disabled)
> > -             return 1;
> >
> >       /*
> >        * Process the Multiple APIC Description Table (MADT), if present
> > Index: linux-pm/arch/x86/kernel/setup.c
> > ===================================================================
> > --- linux-pm.orig/arch/x86/kernel/setup.c
> > +++ linux-pm/arch/x86/kernel/setup.c
> > @@ -1045,6 +1045,9 @@ void __init setup_arch(char **cmdline_p)
> >
> >       cleanup_highmap();
> >
> > +     /* Look for ACPI tables and reserve memory occupied by them. */
> > +     acpi_boot_table_init();
> > +
> >       memblock_set_current_limit(ISA_END_ADDRESS);
> >       e820__memblock_setup();
> >
> > @@ -1136,11 +1139,6 @@ void __init setup_arch(char **cmdline_p)
> >
> >       early_platform_quirks();
> >
> > -     /*
> > -      * Parse the ACPI tables for possible boot-time SMP configuration.
> > -      */
> > -     acpi_boot_table_init();
> > -
> >       early_acpi_boot_init();
> >
> >       initmem_init();
> > Index: linux-pm/include/linux/acpi.h
> > ===================================================================
> > --- linux-pm.orig/include/linux/acpi.h
> > +++ linux-pm/include/linux/acpi.h
> > @@ -222,10 +222,14 @@ void __iomem *__acpi_map_table(unsigned
> >  void __acpi_unmap_table(void __iomem *map, unsigned long size);
> >  int early_acpi_boot_init(void);
> >  int acpi_boot_init (void);
> > +void acpi_boot_table_prepare (void);
> >  void acpi_boot_table_init (void);
> >  int acpi_mps_check (void);
> >  int acpi_numa_init (void);
> >
> > +int acpi_locate_initial_tables (void);
> > +void acpi_reserve_initial_tables (void);
> > +void acpi_table_init_complete (void);
> >  int acpi_table_init (void);
> >  int acpi_table_parse(char *id, acpi_tbl_table_handler handler);
> >  int __init acpi_table_parse_entries(char *id, unsigned long table_size,
> > @@ -814,9 +818,12 @@ static inline int acpi_boot_init(void)
> >       return 0;
> >  }
> >
> > +static inline void acpi_boot_table_prepare(void)
> > +{
> > +}
> > +
> >  static inline void acpi_boot_table_init(void)
> >  {
> > -     return;
> >  }
> >
> >  static inline int acpi_mps_check(void)
> > Index: linux-pm/drivers/acpi/tables.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/tables.c
> > +++ linux-pm/drivers/acpi/tables.c
> > @@ -780,7 +780,7 @@ acpi_status acpi_os_table_override(struc
> >  }
> >
> >  /*
> > - * acpi_table_init()
> > + * acpi_locate_initial_tables()
> >   *
> >   * find RSDP, find and checksum SDT/XSDT.
> >   * checksum all tables, print SDT/XSDT
> > @@ -788,7 +788,7 @@ acpi_status acpi_os_table_override(struc
> >   * result: sdt_entry[] is initialized
> >   */
> >
> > -int __init acpi_table_init(void)
> > +int __init acpi_locate_initial_tables(void)
> >  {
> >       acpi_status status;
> >
> > @@ -803,9 +803,45 @@ int __init acpi_table_init(void)
> >       status = acpi_initialize_tables(initial_tables, ACPI_MAX_TABLES, 0);
> >       if (ACPI_FAILURE(status))
> >               return -EINVAL;
> > -     acpi_table_initrd_scan();
> >
> > +     return 0;
> > +}
> > +
> > +void __init acpi_reserve_initial_tables(void)
> > +{
> > +     int i;
> > +
> > +     for (i = 0; i < ACPI_MAX_TABLES; i++) {
> > +             struct acpi_table_desc *table_desc = &initial_tables[i];
> > +             u64 start = table_desc->address;
> > +             u64 size = table_desc->length;
> > +
> > +             if (!start || !size)
> > +                     break;
> > +
> > +             pr_info("Reserving %4s table memory at [mem 0x%llx-0x%llx]\n",
> > +                     table_desc->signature.ascii, start, start + size - 1);
> > +
> > +             memblock_reserve(start, size);
> > +     }
> > +}
> > +
> > +void __init acpi_table_init_complete(void)
> > +{
> > +     acpi_table_initrd_scan();
> >       check_multiple_madt();
> > +}
> > +
> > +int __init acpi_table_init(void)
> > +{
> > +     int ret;
> > +
> > +     ret = acpi_locate_initial_tables();
> > +     if (ret)
> > +             return ret;
> > +
> > +     acpi_table_init_complete();
> > +
> >       return 0;
> >  }
> >
> >
> >
> >
>
> --
> Sincerely yours,
> Mike.