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[PATCH] x86_64: Fix fast check in safe_smp_processor_id

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The APIC ID returned by hard_smp_processor_id can be beyond
NR_CPUS and then overflow the x86_cpu_to_apic[] array.

Add a check for overflow. If it happens then the slow loop below
will catch.

Bug pointed out by Doug Thompson

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2006-06-26 13:59:17 +02:00 committed by Linus Torvalds
parent e42f943737
commit 75bd665cc9
1 changed files with 2 additions and 2 deletions
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4
arch/x86_64/kernel/smp.c
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@ -520,13 +520,13 @@ asmlinkage void smp_call_function_interrupt(void)
int safe_smp_processor_id(void)
{
int apicid, i;
unsigned apicid, i;
if (disable_apic)
return 0;
apicid = hard_smp_processor_id();
if (x86_cpu_to_apicid[apicid] == apicid)
if (apicid < NR_CPUS && x86_cpu_to_apicid[apicid] == apicid)
return apicid;
for (i = 0; i < NR_CPUS; ++i) {