diff options
| author | Li RongQing <lirongqing@baidu.com> | 2018-04-10 09:16:06 +0800 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-04-10 16:46:39 +0200 |
| commit | a774635db5c430cbf21fa5d2f2df3d23aaa8e782 (patch) | |
| tree | 901a79ca1293a6ef62e57de71e74496347f1ad35 /arch/x86/kernel/acpi | |
| parent | d94a155c59c98c19b98ee949eaab6a0312bbd6be (diff) | |
| download | linux-a774635db5c430cbf21fa5d2f2df3d23aaa8e782.tar.bz2 | |
x86/apic: Fix signedness bug in APIC ID validity checks
The APIC ID as parsed from ACPI MADT is validity checked with the
apic->apic_id_valid() callback, which depends on the selected APIC type.
For non X2APIC types APIC IDs >= 0xFF are invalid, but values > 0x7FFFFFFF
are detected as valid. This happens because the 'apicid' argument of the
apic_id_valid() callback is type 'int'. So the resulting comparison
apicid < 0xFF
evaluates to true for all unsigned int values > 0x7FFFFFFF which are handed
to default_apic_id_valid(). As a consequence, invalid APIC IDs in !X2APIC
mode are considered valid and accounted as possible CPUs.
Change the apicid argument type of the apic_id_valid() callback to u32 so
the evaluation is unsigned and returns the correct result.
[ tglx: Massaged changelog ]
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: jgross@suse.com
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/1523322966-10296-1-git-send-email-lirongqing@baidu.com
Diffstat (limited to 'arch/x86/kernel/acpi')
| -rw-r--r-- | arch/x86/kernel/acpi/boot.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 2aa92094b59d..5ee33a6e33bb 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -200,7 +200,7 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end) { struct acpi_madt_local_x2apic *processor = NULL; #ifdef CONFIG_X86_X2APIC - int apic_id; + u32 apic_id; u8 enabled; #endif @@ -222,10 +222,13 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end) * to not preallocating memory for all NR_CPUS * when we use CPU hotplug. */ - if (!apic->apic_id_valid(apic_id) && enabled) - printk(KERN_WARNING PREFIX "x2apic entry ignored\n"); - else - acpi_register_lapic(apic_id, processor->uid, enabled); + if (!apic->apic_id_valid(apic_id)) { + if (enabled) + pr_warn(PREFIX "x2apic entry ignored\n"); + return 0; + } + + acpi_register_lapic(apic_id, processor->uid, enabled); #else printk(KERN_WARNING PREFIX "x2apic entry ignored\n"); #endif |