| commit | a774635db5c430cbf21fa5d2f2df3d23aaa8e782 | |
| author | Li RongQing <lirongqing@baidu.com> | |
| Tue, 10 Apr 2018 01:16:06 +0000 (10 09:16 +0800) | ||
| committer | Thomas Gleixner <tglx@linutronix.de> | |
| Tue, 10 Apr 2018 14:46:39 +0000 (10 16:46 +0200) | ||
| tree | 901a79ca1293a6ef62e57de71e74496347f1ad35 | treesnapshot (tar.gz zip) |
| parent | d94a155c59c98c19b98ee949eaab6a0312bbd6be | commitdiff |
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
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