Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7bf0c23e authored Jan 30, 2008 by Mike Travis Committed by Ingo Molnar Jan 30, 2008

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>

parent 0fa376e0

arch/x86/kernel/smp_32.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

arch/x86/kernel/smpboot_32.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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));
		}

arch/x86/xen/smp.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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