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x86: prevent dereferencing non-allocated per_cpu variables

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'for_each_possible_cpu(i)' when there's a _remote possibility_ of
dereferencing a non-allocated per_cpu variable involved.

All files except mm/vmstat.c are x86 arch.

Thanks to pageexec@freemail.hu for pointing this out.

Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: <pageexec@freemail.hu>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Mike Travis 2008-01-30 13:30:55 +01:00 committed by Ingo Molnar
parent 0fa376e027
commit 7bf0c23ed2
3 changed files with 6 additions and 6 deletions
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4
arch/x86/kernel/smp_32.c
View File

@ -223,7 +223,7 @@ void send_IPI_mask_sequence(cpumask_t mask, int vector)
*/
local_irq_save(flags);
for (query_cpu = 0; query_cpu < NR_CPUS; ++query_cpu) {
for_each_possible_cpu(query_cpu) {
if (cpu_isset(query_cpu, mask)) {
__send_IPI_dest_field(cpu_to_logical_apicid(query_cpu),
vector);
@ -675,7 +675,7 @@ static int convert_apicid_to_cpu(int apic_id)
{
int i;
for (i = 0; i < NR_CPUS; i++) {
for_each_possible_cpu(i) {
if (per_cpu(x86_cpu_to_apicid, i) == apic_id)
return i;
}

4
arch/x86/kernel/smpboot_32.c
View File

@ -1090,7 +1090,7 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
* Allow the user to impress friends.
*/
Dprintk("Before bogomips.\n");
for (cpu = 0; cpu < NR_CPUS; cpu++)
for_each_possible_cpu(cpu)
if (cpu_isset(cpu, cpu_callout_map))
bogosum += cpu_data(cpu).loops_per_jiffy;
printk(KERN_INFO
@ -1121,7 +1121,7 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
* construct cpu_sibling_map, so that we can tell sibling CPUs
* efficiently.
*/
for (cpu = 0; cpu < NR_CPUS; cpu++) {
for_each_possible_cpu(cpu) {
cpus_clear(per_cpu(cpu_sibling_map, cpu));
cpus_clear(per_cpu(cpu_core_map, cpu));
}

4
arch/x86/xen/smp.c
View File

@ -146,7 +146,7 @@ void __init xen_smp_prepare_boot_cpu(void)
old memory can be recycled */
make_lowmem_page_readwrite(&per_cpu__gdt_page);
for (cpu = 0; cpu < NR_CPUS; cpu++) {
for_each_possible_cpu(cpu) {
cpus_clear(per_cpu(cpu_sibling_map, cpu));
/*
* cpu_core_map lives in a per cpu area that is cleared
@ -163,7 +163,7 @@ void __init xen_smp_prepare_cpus(unsigned int max_cpus)
{
unsigned cpu;
for (cpu = 0; cpu < NR_CPUS; cpu++) {
for_each_possible_cpu(cpu) {
cpus_clear(per_cpu(cpu_sibling_map, cpu));
/*
* cpu_core_ map will be zeroed when the per