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

Mike Rapoport
2021-03-24T08:25:30Z

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

FWIW:
Reviewed-by: Mike Rapoport <rppt@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.