x86: prevent dereferencing non-allocated per_cpu variables
'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>
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index c1b131b..8e1234e 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -146,7 +146,7 @@
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 @@
{
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