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/kernel/smpboot_32.c b/arch/x86/kernel/smpboot_32.c
index 239ada1..0bf7f20 100644
--- a/arch/x86/kernel/smpboot_32.c
+++ b/arch/x86/kernel/smpboot_32.c
@@ -1090,7 +1090,7 @@
* 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 @@
* 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));
}