On Tue, Mar 23, 2021 at 08:26:52PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> 
> 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.kenn...@oracle.com/
> Reported-by: George Kennedy <george.kenn...@oracle.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>

FWIW:
Reviewed-by: Mike Rapoport <r...@linux.ibm.com>

> ---
>  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.

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