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

Rafael J. Wysocki
2021-03-24T13:28:52Z

On Wed, Mar 24, 2021 at 9:24 AM Mike Rapoport <rppt@linux.ibm.com> wrote:
>
> 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>

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.