From a774635db5c430cbf21fa5d2f2df3d23aaa8e782 Mon Sep 17 00:00:00 2001 From: Li RongQing Date: Tue, 10 Apr 2018 09:16:06 +0800 Subject: 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 Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Cc: jgross@suse.com Cc: Dou Liyang Cc: Peter Zijlstra Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/1523322966-10296-1-git-send-email-lirongqing@baidu.com --- arch/x86/include/asm/apic.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 9872277..f01eef8 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -319,7 +319,7 @@ struct apic { /* Probe, setup and smpboot functions */ int (*probe)(void); int (*acpi_madt_oem_check)(char *oem_id, char *oem_table_id); - int (*apic_id_valid)(int apicid); + int (*apic_id_valid)(u32 apicid); int (*apic_id_registered)(void); bool (*check_apicid_used)(physid_mask_t *map, int apicid); @@ -492,7 +492,7 @@ static inline unsigned int read_apic_id(void) return apic->get_apic_id(reg); } -extern int default_apic_id_valid(int apicid); +extern int default_apic_id_valid(u32 apicid); extern int default_acpi_madt_oem_check(char *, char *); extern void default_setup_apic_routing(void); -- cgit v1.1