From 1a1c130ab7575498eed5bcf7220037ae09cd1f8a Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 23 Mar 2021 20:26:52 +0100 Subject: ACPI: tables: x86: Reserve memory occupied by ACPI tables 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 Tested-by: George Kennedy Signed-off-by: Rafael J. Wysocki Reviewed-by: Mike Rapoport Cc: 5.10+ # 5.10+ --- arch/x86/kernel/acpi/boot.c | 25 ++++++++++++------------- arch/x86/kernel/setup.c | 8 +++----- 2 files changed, 15 insertions(+), 18 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 7bdc0239a943..14cd3186dc77 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/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 diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index d883176ef2ce..5ecd69a48393 100644 --- a/arch/x86/kernel/setup.c +++ b/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(); -- cgit v1.2.3