2008-06-26 03:21:34 -06:00
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/*
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* Generic helpers for smp ipi calls
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*
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* (C) Jens Axboe <jens.axboe@oracle.com> 2008
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/percpu.h>
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#include <linux/rcupdate.h>
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2008-07-15 15:02:33 -06:00
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#include <linux/rculist.h>
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2008-06-26 03:21:34 -06:00
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#include <linux/smp.h>
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static DEFINE_PER_CPU(struct call_single_queue, call_single_queue);
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static LIST_HEAD(call_function_queue);
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__cacheline_aligned_in_smp DEFINE_SPINLOCK(call_function_lock);
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enum {
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CSD_FLAG_WAIT = 0x01,
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CSD_FLAG_ALLOC = 0x02,
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};
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struct call_function_data {
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struct call_single_data csd;
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spinlock_t lock;
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unsigned int refs;
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cpumask_t cpumask;
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struct rcu_head rcu_head;
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};
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struct call_single_queue {
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struct list_head list;
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spinlock_t lock;
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};
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2008-07-25 20:45:11 -06:00
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static int __cpuinit init_call_single_data(void)
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2008-06-26 03:21:34 -06:00
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{
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int i;
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for_each_possible_cpu(i) {
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struct call_single_queue *q = &per_cpu(call_single_queue, i);
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spin_lock_init(&q->lock);
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INIT_LIST_HEAD(&q->list);
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}
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2008-07-25 20:45:11 -06:00
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return 0;
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2008-06-26 03:21:34 -06:00
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}
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2008-07-25 20:45:11 -06:00
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early_initcall(init_call_single_data);
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2008-06-26 03:21:34 -06:00
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static void csd_flag_wait(struct call_single_data *data)
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{
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/* Wait for response */
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do {
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/*
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* We need to see the flags store in the IPI handler
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*/
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smp_mb();
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if (!(data->flags & CSD_FLAG_WAIT))
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break;
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cpu_relax();
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} while (1);
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}
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/*
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* Insert a previously allocated call_single_data element for execution
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* on the given CPU. data must already have ->func, ->info, and ->flags set.
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*/
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static void generic_exec_single(int cpu, struct call_single_data *data)
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{
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struct call_single_queue *dst = &per_cpu(call_single_queue, cpu);
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int wait = data->flags & CSD_FLAG_WAIT, ipi;
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unsigned long flags;
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spin_lock_irqsave(&dst->lock, flags);
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ipi = list_empty(&dst->list);
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list_add_tail(&data->list, &dst->list);
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spin_unlock_irqrestore(&dst->lock, flags);
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if (ipi)
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arch_send_call_function_single_ipi(cpu);
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if (wait)
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csd_flag_wait(data);
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}
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static void rcu_free_call_data(struct rcu_head *head)
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{
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struct call_function_data *data;
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data = container_of(head, struct call_function_data, rcu_head);
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kfree(data);
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}
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/*
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* Invoked by arch to handle an IPI for call function. Must be called with
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* interrupts disabled.
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*/
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void generic_smp_call_function_interrupt(void)
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{
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struct call_function_data *data;
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int cpu = get_cpu();
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/*
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* It's ok to use list_for_each_rcu() here even though we may delete
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* 'pos', since list_del_rcu() doesn't clear ->next
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*/
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rcu_read_lock();
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list_for_each_entry_rcu(data, &call_function_queue, csd.list) {
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int refs;
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if (!cpu_isset(cpu, data->cpumask))
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continue;
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data->csd.func(data->csd.info);
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spin_lock(&data->lock);
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cpu_clear(cpu, data->cpumask);
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WARN_ON(data->refs == 0);
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data->refs--;
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refs = data->refs;
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spin_unlock(&data->lock);
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if (refs)
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continue;
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spin_lock(&call_function_lock);
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list_del_rcu(&data->csd.list);
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spin_unlock(&call_function_lock);
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if (data->csd.flags & CSD_FLAG_WAIT) {
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/*
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* serialize stores to data with the flag clear
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* and wakeup
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*/
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smp_wmb();
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data->csd.flags &= ~CSD_FLAG_WAIT;
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} else
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call_rcu(&data->rcu_head, rcu_free_call_data);
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}
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rcu_read_unlock();
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put_cpu();
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}
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/*
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* Invoked by arch to handle an IPI for call function single. Must be called
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* from the arch with interrupts disabled.
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*/
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void generic_smp_call_function_single_interrupt(void)
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{
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struct call_single_queue *q = &__get_cpu_var(call_single_queue);
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LIST_HEAD(list);
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/*
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* Need to see other stores to list head for checking whether
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* list is empty without holding q->lock
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*/
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smp_mb();
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while (!list_empty(&q->list)) {
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unsigned int data_flags;
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spin_lock(&q->lock);
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list_replace_init(&q->list, &list);
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spin_unlock(&q->lock);
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while (!list_empty(&list)) {
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struct call_single_data *data;
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data = list_entry(list.next, struct call_single_data,
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list);
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list_del(&data->list);
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/*
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* 'data' can be invalid after this call if
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* flags == 0 (when called through
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* generic_exec_single(), so save them away before
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* making the call.
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*/
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data_flags = data->flags;
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data->func(data->info);
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if (data_flags & CSD_FLAG_WAIT) {
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smp_wmb();
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data->flags &= ~CSD_FLAG_WAIT;
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} else if (data_flags & CSD_FLAG_ALLOC)
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kfree(data);
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}
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/*
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* See comment on outer loop
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*/
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smp_mb();
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}
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}
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/*
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* smp_call_function_single - Run a function on a specific CPU
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* @func: The function to run. This must be fast and non-blocking.
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* @info: An arbitrary pointer to pass to the function.
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* @wait: If true, wait until function has completed on other CPUs.
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*
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* Returns 0 on success, else a negative status code. Note that @wait
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* will be implicitly turned on in case of allocation failures, since
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* we fall back to on-stack allocation.
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*/
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int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
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2008-06-06 03:18:06 -06:00
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int wait)
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2008-06-26 03:21:34 -06:00
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{
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struct call_single_data d;
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unsigned long flags;
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/* prevent preemption and reschedule on another processor */
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int me = get_cpu();
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/* Can deadlock when called with interrupts disabled */
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WARN_ON(irqs_disabled());
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if (cpu == me) {
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local_irq_save(flags);
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func(info);
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local_irq_restore(flags);
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} else {
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struct call_single_data *data = NULL;
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if (!wait) {
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data = kmalloc(sizeof(*data), GFP_ATOMIC);
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if (data)
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data->flags = CSD_FLAG_ALLOC;
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}
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if (!data) {
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data = &d;
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data->flags = CSD_FLAG_WAIT;
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}
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data->func = func;
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data->info = info;
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generic_exec_single(cpu, data);
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}
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put_cpu();
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return 0;
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}
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EXPORT_SYMBOL(smp_call_function_single);
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/**
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* __smp_call_function_single(): Run a function on another CPU
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* @cpu: The CPU to run on.
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* @data: Pre-allocated and setup data structure
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*
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* Like smp_call_function_single(), but allow caller to pass in a pre-allocated
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* data structure. Useful for embedding @data inside other structures, for
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* instance.
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*
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*/
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void __smp_call_function_single(int cpu, struct call_single_data *data)
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{
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/* Can deadlock when called with interrupts disabled */
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WARN_ON((data->flags & CSD_FLAG_WAIT) && irqs_disabled());
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generic_exec_single(cpu, data);
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}
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generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask()
* Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote:
> Found a OOPS on a big SMP box during an overnight reboot test with
> upstream git.
>
> Suresh and I looked at the oops and looks like the root cause is in
> generic_smp_call_function_interrupt() and smp_call_function_mask() with
> wait parameter.
>
> The actual oops looked like
>
> [ 11.277260] BUG: unable to handle kernel paging request at ffff8802ffffffff
> [ 11.277815] IP: [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.278155] PGD 202063 PUD 0
> [ 11.278576] Oops: 0010 [1] SMP
> [ 11.279006] CPU 5
> [ 11.279336] Modules linked in:
> [ 11.279752] Pid: 0, comm: swapper Not tainted 2.6.27-rc2-00020-g685d87f #290
> [ 11.280039] RIP: 0010:[<ffff8802ffffffff>] [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.280692] RSP: 0018:ffff88027f1f7f70 EFLAGS: 00010086
> [ 11.280976] RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000
> [ 11.281264] RDX: 0000000000004f4e RSI: 0000000000000001 RDI: 0000000000000000
> [ 11.281624] RBP: ffff88027f1f7f98 R08: 0000000000000001 R09: ffffffff802509af
> [ 11.281925] R10: ffff8800280c2780 R11: 0000000000000000 R12: ffff88027f097d48
> [ 11.282214] R13: ffff88027f097d70 R14: 0000000000000005 R15: ffff88027e571000
> [ 11.282502] FS: 0000000000000000(0000) GS:ffff88027f1c3340(0000) knlGS:0000000000000000
> [ 11.283096] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> [ 11.283382] CR2: ffff8802ffffffff CR3: 0000000000201000 CR4: 00000000000006e0
> [ 11.283760] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 11.284048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 11.284337] Process swapper (pid: 0, threadinfo ffff88027f1f2000, task ffff88027f1f0640)
> [ 11.284936] Stack: ffffffff80250963 0000000000000212 0000000000ee8c78 0000000000ee8a66
> [ 11.285802] ffff88027e571550 ffff88027f1f7fa8 ffffffff8021adb5 ffff88027f1f3e40
> [ 11.286599] ffffffff8020bdd6 ffff88027f1f3e40 <EOI> ffff88027f1f3ef8 0000000000000000
> [ 11.287120] Call Trace:
> [ 11.287768] <IRQ> [<ffffffff80250963>] ? generic_smp_call_function_interrupt+0x61/0x12c
> [ 11.288354] [<ffffffff8021adb5>] smp_call_function_interrupt+0x17/0x27
> [ 11.288744] [<ffffffff8020bdd6>] call_function_interrupt+0x66/0x70
> [ 11.289030] <EOI> [<ffffffff8024ab3b>] ? clockevents_notify+0x19/0x73
> [ 11.289380] [<ffffffff803b9b75>] ? acpi_idle_enter_simple+0x18b/0x1fa
> [ 11.289760] [<ffffffff803b9b6b>] ? acpi_idle_enter_simple+0x181/0x1fa
> [ 11.290051] [<ffffffff8053aeca>] ? cpuidle_idle_call+0x70/0xa2
> [ 11.290338] [<ffffffff80209f61>] ? cpu_idle+0x5f/0x7d
> [ 11.290723] [<ffffffff8060224a>] ? start_secondary+0x14d/0x152
> [ 11.291010]
> [ 11.291287]
> [ 11.291654] Code: Bad RIP value.
> [ 11.292041] RIP [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.292380] RSP <ffff88027f1f7f70>
> [ 11.292741] CR2: ffff8802ffffffff
> [ 11.310951] ---[ end trace 137c54d525305f1c ]---
>
> The problem is with the following sequence of events:
>
> - CPU A calls smp_call_function_mask() for CPU B with wait parameter
> - CPU A sets up the call_function_data on the stack and does an rcu add to
> call_function_queue
> - CPU A waits until the WAIT flag is cleared
> - CPU B gets the call function interrupt and starts going through the
> call_function_queue
> - CPU C also gets some other call function interrupt and starts going through
> the call_function_queue
> - CPU C, which is also going through the call_function_queue, starts referencing
> CPU A's stack, as that element is still in call_function_queue
> - CPU B finishes the function call that CPU A set up and as there are no other
> references to it, rcu deletes the call_function_data (which was from CPU A
> stack)
> - CPU B sees the wait flag and just clears the flag (no call_rcu to free)
> - CPU A which was waiting on the flag continues executing and the stack
> contents change
>
> - CPU C is still in rcu_read section accessing the CPU A's stack sees
> inconsistent call_funation_data and can try to execute
> function with some random pointer, causing stack corruption for A
> (by clearing the bits in mask field) and oops.
Nice debugging work.
I'd suggest something like the attached (boot tested) patch as the simple
fix for now.
I expect the benefits from the less synchronized, multiple-in-flight-data
global queue will still outweigh the costs of dynamic allocations. But
if worst comes to worst then we just go back to a globally synchronous
one-at-a-time implementation, but that would be pretty sad!
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-10 21:49:30 -06:00
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/* Dummy function */
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static void quiesce_dummy(void *unused)
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{
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}
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/*
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* Ensure stack based data used in call function mask is safe to free.
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*
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* This is needed by smp_call_function_mask when using on-stack data, because
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* a single call function queue is shared by all CPUs, and any CPU may pick up
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* the data item on the queue at any time before it is deleted. So we need to
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* ensure that all CPUs have transitioned through a quiescent state after
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* this call.
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*
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* This is a very slow function, implemented by sending synchronous IPIs to
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* all possible CPUs. For this reason, we have to alloc data rather than use
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* stack based data even in the case of synchronous calls. The stack based
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* data is then just used for deadlock/oom fallback which will be very rare.
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*
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* If a faster scheme can be made, we could go back to preferring stack based
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* data -- the data allocation/free is non-zero cost.
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*/
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static void smp_call_function_mask_quiesce_stack(cpumask_t mask)
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{
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struct call_single_data data;
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int cpu;
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data.func = quiesce_dummy;
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data.info = NULL;
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data.flags = CSD_FLAG_WAIT;
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for_each_cpu_mask(cpu, mask)
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generic_exec_single(cpu, &data);
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}
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|
2008-06-26 03:21:34 -06:00
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/**
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* smp_call_function_mask(): Run a function on a set of other CPUs.
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* @mask: The set of cpus to run on.
|
|
|
|
* @func: The function to run. This must be fast and non-blocking.
|
|
|
|
* @info: An arbitrary pointer to pass to the function.
|
|
|
|
* @wait: If true, wait (atomically) until function has completed on other CPUs.
|
|
|
|
*
|
|
|
|
* Returns 0 on success, else a negative status code.
|
|
|
|
*
|
|
|
|
* If @wait is true, then returns once @func has returned. Note that @wait
|
|
|
|
* will be implicitly turned on in case of allocation failures, since
|
|
|
|
* we fall back to on-stack allocation.
|
|
|
|
*
|
|
|
|
* You must not call this function with disabled interrupts or from a
|
|
|
|
* hardware interrupt handler or from a bottom half handler. Preemption
|
|
|
|
* must be disabled when calling this function.
|
|
|
|
*/
|
|
|
|
int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info,
|
|
|
|
int wait)
|
|
|
|
{
|
|
|
|
struct call_function_data d;
|
|
|
|
struct call_function_data *data = NULL;
|
|
|
|
cpumask_t allbutself;
|
|
|
|
unsigned long flags;
|
|
|
|
int cpu, num_cpus;
|
generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask()
* Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote:
> Found a OOPS on a big SMP box during an overnight reboot test with
> upstream git.
>
> Suresh and I looked at the oops and looks like the root cause is in
> generic_smp_call_function_interrupt() and smp_call_function_mask() with
> wait parameter.
>
> The actual oops looked like
>
> [ 11.277260] BUG: unable to handle kernel paging request at ffff8802ffffffff
> [ 11.277815] IP: [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.278155] PGD 202063 PUD 0
> [ 11.278576] Oops: 0010 [1] SMP
> [ 11.279006] CPU 5
> [ 11.279336] Modules linked in:
> [ 11.279752] Pid: 0, comm: swapper Not tainted 2.6.27-rc2-00020-g685d87f #290
> [ 11.280039] RIP: 0010:[<ffff8802ffffffff>] [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.280692] RSP: 0018:ffff88027f1f7f70 EFLAGS: 00010086
> [ 11.280976] RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000
> [ 11.281264] RDX: 0000000000004f4e RSI: 0000000000000001 RDI: 0000000000000000
> [ 11.281624] RBP: ffff88027f1f7f98 R08: 0000000000000001 R09: ffffffff802509af
> [ 11.281925] R10: ffff8800280c2780 R11: 0000000000000000 R12: ffff88027f097d48
> [ 11.282214] R13: ffff88027f097d70 R14: 0000000000000005 R15: ffff88027e571000
> [ 11.282502] FS: 0000000000000000(0000) GS:ffff88027f1c3340(0000) knlGS:0000000000000000
> [ 11.283096] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> [ 11.283382] CR2: ffff8802ffffffff CR3: 0000000000201000 CR4: 00000000000006e0
> [ 11.283760] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 11.284048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 11.284337] Process swapper (pid: 0, threadinfo ffff88027f1f2000, task ffff88027f1f0640)
> [ 11.284936] Stack: ffffffff80250963 0000000000000212 0000000000ee8c78 0000000000ee8a66
> [ 11.285802] ffff88027e571550 ffff88027f1f7fa8 ffffffff8021adb5 ffff88027f1f3e40
> [ 11.286599] ffffffff8020bdd6 ffff88027f1f3e40 <EOI> ffff88027f1f3ef8 0000000000000000
> [ 11.287120] Call Trace:
> [ 11.287768] <IRQ> [<ffffffff80250963>] ? generic_smp_call_function_interrupt+0x61/0x12c
> [ 11.288354] [<ffffffff8021adb5>] smp_call_function_interrupt+0x17/0x27
> [ 11.288744] [<ffffffff8020bdd6>] call_function_interrupt+0x66/0x70
> [ 11.289030] <EOI> [<ffffffff8024ab3b>] ? clockevents_notify+0x19/0x73
> [ 11.289380] [<ffffffff803b9b75>] ? acpi_idle_enter_simple+0x18b/0x1fa
> [ 11.289760] [<ffffffff803b9b6b>] ? acpi_idle_enter_simple+0x181/0x1fa
> [ 11.290051] [<ffffffff8053aeca>] ? cpuidle_idle_call+0x70/0xa2
> [ 11.290338] [<ffffffff80209f61>] ? cpu_idle+0x5f/0x7d
> [ 11.290723] [<ffffffff8060224a>] ? start_secondary+0x14d/0x152
> [ 11.291010]
> [ 11.291287]
> [ 11.291654] Code: Bad RIP value.
> [ 11.292041] RIP [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.292380] RSP <ffff88027f1f7f70>
> [ 11.292741] CR2: ffff8802ffffffff
> [ 11.310951] ---[ end trace 137c54d525305f1c ]---
>
> The problem is with the following sequence of events:
>
> - CPU A calls smp_call_function_mask() for CPU B with wait parameter
> - CPU A sets up the call_function_data on the stack and does an rcu add to
> call_function_queue
> - CPU A waits until the WAIT flag is cleared
> - CPU B gets the call function interrupt and starts going through the
> call_function_queue
> - CPU C also gets some other call function interrupt and starts going through
> the call_function_queue
> - CPU C, which is also going through the call_function_queue, starts referencing
> CPU A's stack, as that element is still in call_function_queue
> - CPU B finishes the function call that CPU A set up and as there are no other
> references to it, rcu deletes the call_function_data (which was from CPU A
> stack)
> - CPU B sees the wait flag and just clears the flag (no call_rcu to free)
> - CPU A which was waiting on the flag continues executing and the stack
> contents change
>
> - CPU C is still in rcu_read section accessing the CPU A's stack sees
> inconsistent call_funation_data and can try to execute
> function with some random pointer, causing stack corruption for A
> (by clearing the bits in mask field) and oops.
Nice debugging work.
I'd suggest something like the attached (boot tested) patch as the simple
fix for now.
I expect the benefits from the less synchronized, multiple-in-flight-data
global queue will still outweigh the costs of dynamic allocations. But
if worst comes to worst then we just go back to a globally synchronous
one-at-a-time implementation, but that would be pretty sad!
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-10 21:49:30 -06:00
|
|
|
int slowpath = 0;
|
2008-06-26 03:21:34 -06:00
|
|
|
|
|
|
|
/* Can deadlock when called with interrupts disabled */
|
|
|
|
WARN_ON(irqs_disabled());
|
|
|
|
|
|
|
|
cpu = smp_processor_id();
|
|
|
|
allbutself = cpu_online_map;
|
|
|
|
cpu_clear(cpu, allbutself);
|
|
|
|
cpus_and(mask, mask, allbutself);
|
|
|
|
num_cpus = cpus_weight(mask);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If zero CPUs, return. If just a single CPU, turn this request
|
|
|
|
* into a targetted single call instead since it's faster.
|
|
|
|
*/
|
|
|
|
if (!num_cpus)
|
|
|
|
return 0;
|
|
|
|
else if (num_cpus == 1) {
|
|
|
|
cpu = first_cpu(mask);
|
2008-06-27 03:50:32 -06:00
|
|
|
return smp_call_function_single(cpu, func, info, wait);
|
2008-06-26 03:21:34 -06:00
|
|
|
}
|
|
|
|
|
generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask()
* Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote:
> Found a OOPS on a big SMP box during an overnight reboot test with
> upstream git.
>
> Suresh and I looked at the oops and looks like the root cause is in
> generic_smp_call_function_interrupt() and smp_call_function_mask() with
> wait parameter.
>
> The actual oops looked like
>
> [ 11.277260] BUG: unable to handle kernel paging request at ffff8802ffffffff
> [ 11.277815] IP: [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.278155] PGD 202063 PUD 0
> [ 11.278576] Oops: 0010 [1] SMP
> [ 11.279006] CPU 5
> [ 11.279336] Modules linked in:
> [ 11.279752] Pid: 0, comm: swapper Not tainted 2.6.27-rc2-00020-g685d87f #290
> [ 11.280039] RIP: 0010:[<ffff8802ffffffff>] [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.280692] RSP: 0018:ffff88027f1f7f70 EFLAGS: 00010086
> [ 11.280976] RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000
> [ 11.281264] RDX: 0000000000004f4e RSI: 0000000000000001 RDI: 0000000000000000
> [ 11.281624] RBP: ffff88027f1f7f98 R08: 0000000000000001 R09: ffffffff802509af
> [ 11.281925] R10: ffff8800280c2780 R11: 0000000000000000 R12: ffff88027f097d48
> [ 11.282214] R13: ffff88027f097d70 R14: 0000000000000005 R15: ffff88027e571000
> [ 11.282502] FS: 0000000000000000(0000) GS:ffff88027f1c3340(0000) knlGS:0000000000000000
> [ 11.283096] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> [ 11.283382] CR2: ffff8802ffffffff CR3: 0000000000201000 CR4: 00000000000006e0
> [ 11.283760] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 11.284048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 11.284337] Process swapper (pid: 0, threadinfo ffff88027f1f2000, task ffff88027f1f0640)
> [ 11.284936] Stack: ffffffff80250963 0000000000000212 0000000000ee8c78 0000000000ee8a66
> [ 11.285802] ffff88027e571550 ffff88027f1f7fa8 ffffffff8021adb5 ffff88027f1f3e40
> [ 11.286599] ffffffff8020bdd6 ffff88027f1f3e40 <EOI> ffff88027f1f3ef8 0000000000000000
> [ 11.287120] Call Trace:
> [ 11.287768] <IRQ> [<ffffffff80250963>] ? generic_smp_call_function_interrupt+0x61/0x12c
> [ 11.288354] [<ffffffff8021adb5>] smp_call_function_interrupt+0x17/0x27
> [ 11.288744] [<ffffffff8020bdd6>] call_function_interrupt+0x66/0x70
> [ 11.289030] <EOI> [<ffffffff8024ab3b>] ? clockevents_notify+0x19/0x73
> [ 11.289380] [<ffffffff803b9b75>] ? acpi_idle_enter_simple+0x18b/0x1fa
> [ 11.289760] [<ffffffff803b9b6b>] ? acpi_idle_enter_simple+0x181/0x1fa
> [ 11.290051] [<ffffffff8053aeca>] ? cpuidle_idle_call+0x70/0xa2
> [ 11.290338] [<ffffffff80209f61>] ? cpu_idle+0x5f/0x7d
> [ 11.290723] [<ffffffff8060224a>] ? start_secondary+0x14d/0x152
> [ 11.291010]
> [ 11.291287]
> [ 11.291654] Code: Bad RIP value.
> [ 11.292041] RIP [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.292380] RSP <ffff88027f1f7f70>
> [ 11.292741] CR2: ffff8802ffffffff
> [ 11.310951] ---[ end trace 137c54d525305f1c ]---
>
> The problem is with the following sequence of events:
>
> - CPU A calls smp_call_function_mask() for CPU B with wait parameter
> - CPU A sets up the call_function_data on the stack and does an rcu add to
> call_function_queue
> - CPU A waits until the WAIT flag is cleared
> - CPU B gets the call function interrupt and starts going through the
> call_function_queue
> - CPU C also gets some other call function interrupt and starts going through
> the call_function_queue
> - CPU C, which is also going through the call_function_queue, starts referencing
> CPU A's stack, as that element is still in call_function_queue
> - CPU B finishes the function call that CPU A set up and as there are no other
> references to it, rcu deletes the call_function_data (which was from CPU A
> stack)
> - CPU B sees the wait flag and just clears the flag (no call_rcu to free)
> - CPU A which was waiting on the flag continues executing and the stack
> contents change
>
> - CPU C is still in rcu_read section accessing the CPU A's stack sees
> inconsistent call_funation_data and can try to execute
> function with some random pointer, causing stack corruption for A
> (by clearing the bits in mask field) and oops.
Nice debugging work.
I'd suggest something like the attached (boot tested) patch as the simple
fix for now.
I expect the benefits from the less synchronized, multiple-in-flight-data
global queue will still outweigh the costs of dynamic allocations. But
if worst comes to worst then we just go back to a globally synchronous
one-at-a-time implementation, but that would be pretty sad!
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-10 21:49:30 -06:00
|
|
|
data = kmalloc(sizeof(*data), GFP_ATOMIC);
|
|
|
|
if (data) {
|
|
|
|
data->csd.flags = CSD_FLAG_ALLOC;
|
|
|
|
if (wait)
|
|
|
|
data->csd.flags |= CSD_FLAG_WAIT;
|
|
|
|
} else {
|
2008-06-26 03:21:34 -06:00
|
|
|
data = &d;
|
|
|
|
data->csd.flags = CSD_FLAG_WAIT;
|
2008-07-15 14:22:49 -06:00
|
|
|
wait = 1;
|
generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask()
* Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote:
> Found a OOPS on a big SMP box during an overnight reboot test with
> upstream git.
>
> Suresh and I looked at the oops and looks like the root cause is in
> generic_smp_call_function_interrupt() and smp_call_function_mask() with
> wait parameter.
>
> The actual oops looked like
>
> [ 11.277260] BUG: unable to handle kernel paging request at ffff8802ffffffff
> [ 11.277815] IP: [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.278155] PGD 202063 PUD 0
> [ 11.278576] Oops: 0010 [1] SMP
> [ 11.279006] CPU 5
> [ 11.279336] Modules linked in:
> [ 11.279752] Pid: 0, comm: swapper Not tainted 2.6.27-rc2-00020-g685d87f #290
> [ 11.280039] RIP: 0010:[<ffff8802ffffffff>] [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.280692] RSP: 0018:ffff88027f1f7f70 EFLAGS: 00010086
> [ 11.280976] RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000
> [ 11.281264] RDX: 0000000000004f4e RSI: 0000000000000001 RDI: 0000000000000000
> [ 11.281624] RBP: ffff88027f1f7f98 R08: 0000000000000001 R09: ffffffff802509af
> [ 11.281925] R10: ffff8800280c2780 R11: 0000000000000000 R12: ffff88027f097d48
> [ 11.282214] R13: ffff88027f097d70 R14: 0000000000000005 R15: ffff88027e571000
> [ 11.282502] FS: 0000000000000000(0000) GS:ffff88027f1c3340(0000) knlGS:0000000000000000
> [ 11.283096] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> [ 11.283382] CR2: ffff8802ffffffff CR3: 0000000000201000 CR4: 00000000000006e0
> [ 11.283760] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 11.284048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 11.284337] Process swapper (pid: 0, threadinfo ffff88027f1f2000, task ffff88027f1f0640)
> [ 11.284936] Stack: ffffffff80250963 0000000000000212 0000000000ee8c78 0000000000ee8a66
> [ 11.285802] ffff88027e571550 ffff88027f1f7fa8 ffffffff8021adb5 ffff88027f1f3e40
> [ 11.286599] ffffffff8020bdd6 ffff88027f1f3e40 <EOI> ffff88027f1f3ef8 0000000000000000
> [ 11.287120] Call Trace:
> [ 11.287768] <IRQ> [<ffffffff80250963>] ? generic_smp_call_function_interrupt+0x61/0x12c
> [ 11.288354] [<ffffffff8021adb5>] smp_call_function_interrupt+0x17/0x27
> [ 11.288744] [<ffffffff8020bdd6>] call_function_interrupt+0x66/0x70
> [ 11.289030] <EOI> [<ffffffff8024ab3b>] ? clockevents_notify+0x19/0x73
> [ 11.289380] [<ffffffff803b9b75>] ? acpi_idle_enter_simple+0x18b/0x1fa
> [ 11.289760] [<ffffffff803b9b6b>] ? acpi_idle_enter_simple+0x181/0x1fa
> [ 11.290051] [<ffffffff8053aeca>] ? cpuidle_idle_call+0x70/0xa2
> [ 11.290338] [<ffffffff80209f61>] ? cpu_idle+0x5f/0x7d
> [ 11.290723] [<ffffffff8060224a>] ? start_secondary+0x14d/0x152
> [ 11.291010]
> [ 11.291287]
> [ 11.291654] Code: Bad RIP value.
> [ 11.292041] RIP [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.292380] RSP <ffff88027f1f7f70>
> [ 11.292741] CR2: ffff8802ffffffff
> [ 11.310951] ---[ end trace 137c54d525305f1c ]---
>
> The problem is with the following sequence of events:
>
> - CPU A calls smp_call_function_mask() for CPU B with wait parameter
> - CPU A sets up the call_function_data on the stack and does an rcu add to
> call_function_queue
> - CPU A waits until the WAIT flag is cleared
> - CPU B gets the call function interrupt and starts going through the
> call_function_queue
> - CPU C also gets some other call function interrupt and starts going through
> the call_function_queue
> - CPU C, which is also going through the call_function_queue, starts referencing
> CPU A's stack, as that element is still in call_function_queue
> - CPU B finishes the function call that CPU A set up and as there are no other
> references to it, rcu deletes the call_function_data (which was from CPU A
> stack)
> - CPU B sees the wait flag and just clears the flag (no call_rcu to free)
> - CPU A which was waiting on the flag continues executing and the stack
> contents change
>
> - CPU C is still in rcu_read section accessing the CPU A's stack sees
> inconsistent call_funation_data and can try to execute
> function with some random pointer, causing stack corruption for A
> (by clearing the bits in mask field) and oops.
Nice debugging work.
I'd suggest something like the attached (boot tested) patch as the simple
fix for now.
I expect the benefits from the less synchronized, multiple-in-flight-data
global queue will still outweigh the costs of dynamic allocations. But
if worst comes to worst then we just go back to a globally synchronous
one-at-a-time implementation, but that would be pretty sad!
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-10 21:49:30 -06:00
|
|
|
slowpath = 1;
|
2008-06-26 03:21:34 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
spin_lock_init(&data->lock);
|
|
|
|
data->csd.func = func;
|
|
|
|
data->csd.info = info;
|
|
|
|
data->refs = num_cpus;
|
|
|
|
data->cpumask = mask;
|
|
|
|
|
|
|
|
spin_lock_irqsave(&call_function_lock, flags);
|
|
|
|
list_add_tail_rcu(&data->csd.list, &call_function_queue);
|
|
|
|
spin_unlock_irqrestore(&call_function_lock, flags);
|
|
|
|
|
|
|
|
/* Send a message to all CPUs in the map */
|
|
|
|
arch_send_call_function_ipi(mask);
|
|
|
|
|
|
|
|
/* optionally wait for the CPUs to complete */
|
generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask()
* Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote:
> Found a OOPS on a big SMP box during an overnight reboot test with
> upstream git.
>
> Suresh and I looked at the oops and looks like the root cause is in
> generic_smp_call_function_interrupt() and smp_call_function_mask() with
> wait parameter.
>
> The actual oops looked like
>
> [ 11.277260] BUG: unable to handle kernel paging request at ffff8802ffffffff
> [ 11.277815] IP: [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.278155] PGD 202063 PUD 0
> [ 11.278576] Oops: 0010 [1] SMP
> [ 11.279006] CPU 5
> [ 11.279336] Modules linked in:
> [ 11.279752] Pid: 0, comm: swapper Not tainted 2.6.27-rc2-00020-g685d87f #290
> [ 11.280039] RIP: 0010:[<ffff8802ffffffff>] [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.280692] RSP: 0018:ffff88027f1f7f70 EFLAGS: 00010086
> [ 11.280976] RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000
> [ 11.281264] RDX: 0000000000004f4e RSI: 0000000000000001 RDI: 0000000000000000
> [ 11.281624] RBP: ffff88027f1f7f98 R08: 0000000000000001 R09: ffffffff802509af
> [ 11.281925] R10: ffff8800280c2780 R11: 0000000000000000 R12: ffff88027f097d48
> [ 11.282214] R13: ffff88027f097d70 R14: 0000000000000005 R15: ffff88027e571000
> [ 11.282502] FS: 0000000000000000(0000) GS:ffff88027f1c3340(0000) knlGS:0000000000000000
> [ 11.283096] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> [ 11.283382] CR2: ffff8802ffffffff CR3: 0000000000201000 CR4: 00000000000006e0
> [ 11.283760] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 11.284048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 11.284337] Process swapper (pid: 0, threadinfo ffff88027f1f2000, task ffff88027f1f0640)
> [ 11.284936] Stack: ffffffff80250963 0000000000000212 0000000000ee8c78 0000000000ee8a66
> [ 11.285802] ffff88027e571550 ffff88027f1f7fa8 ffffffff8021adb5 ffff88027f1f3e40
> [ 11.286599] ffffffff8020bdd6 ffff88027f1f3e40 <EOI> ffff88027f1f3ef8 0000000000000000
> [ 11.287120] Call Trace:
> [ 11.287768] <IRQ> [<ffffffff80250963>] ? generic_smp_call_function_interrupt+0x61/0x12c
> [ 11.288354] [<ffffffff8021adb5>] smp_call_function_interrupt+0x17/0x27
> [ 11.288744] [<ffffffff8020bdd6>] call_function_interrupt+0x66/0x70
> [ 11.289030] <EOI> [<ffffffff8024ab3b>] ? clockevents_notify+0x19/0x73
> [ 11.289380] [<ffffffff803b9b75>] ? acpi_idle_enter_simple+0x18b/0x1fa
> [ 11.289760] [<ffffffff803b9b6b>] ? acpi_idle_enter_simple+0x181/0x1fa
> [ 11.290051] [<ffffffff8053aeca>] ? cpuidle_idle_call+0x70/0xa2
> [ 11.290338] [<ffffffff80209f61>] ? cpu_idle+0x5f/0x7d
> [ 11.290723] [<ffffffff8060224a>] ? start_secondary+0x14d/0x152
> [ 11.291010]
> [ 11.291287]
> [ 11.291654] Code: Bad RIP value.
> [ 11.292041] RIP [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.292380] RSP <ffff88027f1f7f70>
> [ 11.292741] CR2: ffff8802ffffffff
> [ 11.310951] ---[ end trace 137c54d525305f1c ]---
>
> The problem is with the following sequence of events:
>
> - CPU A calls smp_call_function_mask() for CPU B with wait parameter
> - CPU A sets up the call_function_data on the stack and does an rcu add to
> call_function_queue
> - CPU A waits until the WAIT flag is cleared
> - CPU B gets the call function interrupt and starts going through the
> call_function_queue
> - CPU C also gets some other call function interrupt and starts going through
> the call_function_queue
> - CPU C, which is also going through the call_function_queue, starts referencing
> CPU A's stack, as that element is still in call_function_queue
> - CPU B finishes the function call that CPU A set up and as there are no other
> references to it, rcu deletes the call_function_data (which was from CPU A
> stack)
> - CPU B sees the wait flag and just clears the flag (no call_rcu to free)
> - CPU A which was waiting on the flag continues executing and the stack
> contents change
>
> - CPU C is still in rcu_read section accessing the CPU A's stack sees
> inconsistent call_funation_data and can try to execute
> function with some random pointer, causing stack corruption for A
> (by clearing the bits in mask field) and oops.
Nice debugging work.
I'd suggest something like the attached (boot tested) patch as the simple
fix for now.
I expect the benefits from the less synchronized, multiple-in-flight-data
global queue will still outweigh the costs of dynamic allocations. But
if worst comes to worst then we just go back to a globally synchronous
one-at-a-time implementation, but that would be pretty sad!
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-10 21:49:30 -06:00
|
|
|
if (wait) {
|
2008-06-26 03:21:34 -06:00
|
|
|
csd_flag_wait(&data->csd);
|
generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask()
* Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote:
> Found a OOPS on a big SMP box during an overnight reboot test with
> upstream git.
>
> Suresh and I looked at the oops and looks like the root cause is in
> generic_smp_call_function_interrupt() and smp_call_function_mask() with
> wait parameter.
>
> The actual oops looked like
>
> [ 11.277260] BUG: unable to handle kernel paging request at ffff8802ffffffff
> [ 11.277815] IP: [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.278155] PGD 202063 PUD 0
> [ 11.278576] Oops: 0010 [1] SMP
> [ 11.279006] CPU 5
> [ 11.279336] Modules linked in:
> [ 11.279752] Pid: 0, comm: swapper Not tainted 2.6.27-rc2-00020-g685d87f #290
> [ 11.280039] RIP: 0010:[<ffff8802ffffffff>] [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.280692] RSP: 0018:ffff88027f1f7f70 EFLAGS: 00010086
> [ 11.280976] RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000
> [ 11.281264] RDX: 0000000000004f4e RSI: 0000000000000001 RDI: 0000000000000000
> [ 11.281624] RBP: ffff88027f1f7f98 R08: 0000000000000001 R09: ffffffff802509af
> [ 11.281925] R10: ffff8800280c2780 R11: 0000000000000000 R12: ffff88027f097d48
> [ 11.282214] R13: ffff88027f097d70 R14: 0000000000000005 R15: ffff88027e571000
> [ 11.282502] FS: 0000000000000000(0000) GS:ffff88027f1c3340(0000) knlGS:0000000000000000
> [ 11.283096] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> [ 11.283382] CR2: ffff8802ffffffff CR3: 0000000000201000 CR4: 00000000000006e0
> [ 11.283760] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 11.284048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 11.284337] Process swapper (pid: 0, threadinfo ffff88027f1f2000, task ffff88027f1f0640)
> [ 11.284936] Stack: ffffffff80250963 0000000000000212 0000000000ee8c78 0000000000ee8a66
> [ 11.285802] ffff88027e571550 ffff88027f1f7fa8 ffffffff8021adb5 ffff88027f1f3e40
> [ 11.286599] ffffffff8020bdd6 ffff88027f1f3e40 <EOI> ffff88027f1f3ef8 0000000000000000
> [ 11.287120] Call Trace:
> [ 11.287768] <IRQ> [<ffffffff80250963>] ? generic_smp_call_function_interrupt+0x61/0x12c
> [ 11.288354] [<ffffffff8021adb5>] smp_call_function_interrupt+0x17/0x27
> [ 11.288744] [<ffffffff8020bdd6>] call_function_interrupt+0x66/0x70
> [ 11.289030] <EOI> [<ffffffff8024ab3b>] ? clockevents_notify+0x19/0x73
> [ 11.289380] [<ffffffff803b9b75>] ? acpi_idle_enter_simple+0x18b/0x1fa
> [ 11.289760] [<ffffffff803b9b6b>] ? acpi_idle_enter_simple+0x181/0x1fa
> [ 11.290051] [<ffffffff8053aeca>] ? cpuidle_idle_call+0x70/0xa2
> [ 11.290338] [<ffffffff80209f61>] ? cpu_idle+0x5f/0x7d
> [ 11.290723] [<ffffffff8060224a>] ? start_secondary+0x14d/0x152
> [ 11.291010]
> [ 11.291287]
> [ 11.291654] Code: Bad RIP value.
> [ 11.292041] RIP [<ffff8802ffffffff>] 0xffff8802ffffffff
> [ 11.292380] RSP <ffff88027f1f7f70>
> [ 11.292741] CR2: ffff8802ffffffff
> [ 11.310951] ---[ end trace 137c54d525305f1c ]---
>
> The problem is with the following sequence of events:
>
> - CPU A calls smp_call_function_mask() for CPU B with wait parameter
> - CPU A sets up the call_function_data on the stack and does an rcu add to
> call_function_queue
> - CPU A waits until the WAIT flag is cleared
> - CPU B gets the call function interrupt and starts going through the
> call_function_queue
> - CPU C also gets some other call function interrupt and starts going through
> the call_function_queue
> - CPU C, which is also going through the call_function_queue, starts referencing
> CPU A's stack, as that element is still in call_function_queue
> - CPU B finishes the function call that CPU A set up and as there are no other
> references to it, rcu deletes the call_function_data (which was from CPU A
> stack)
> - CPU B sees the wait flag and just clears the flag (no call_rcu to free)
> - CPU A which was waiting on the flag continues executing and the stack
> contents change
>
> - CPU C is still in rcu_read section accessing the CPU A's stack sees
> inconsistent call_funation_data and can try to execute
> function with some random pointer, causing stack corruption for A
> (by clearing the bits in mask field) and oops.
Nice debugging work.
I'd suggest something like the attached (boot tested) patch as the simple
fix for now.
I expect the benefits from the less synchronized, multiple-in-flight-data
global queue will still outweigh the costs of dynamic allocations. But
if worst comes to worst then we just go back to a globally synchronous
one-at-a-time implementation, but that would be pretty sad!
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-10 21:49:30 -06:00
|
|
|
if (unlikely(slowpath))
|
|
|
|
smp_call_function_mask_quiesce_stack(allbutself);
|
|
|
|
}
|
2008-06-26 03:21:34 -06:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(smp_call_function_mask);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* smp_call_function(): Run a function on all other CPUs.
|
|
|
|
* @func: The function to run. This must be fast and non-blocking.
|
|
|
|
* @info: An arbitrary pointer to pass to the function.
|
|
|
|
* @wait: If true, wait (atomically) until function has completed on other CPUs.
|
|
|
|
*
|
|
|
|
* Returns 0 on success, else a negative status code.
|
|
|
|
*
|
|
|
|
* If @wait is true, then returns once @func has returned; otherwise
|
|
|
|
* it returns just before the target cpu calls @func. In case of allocation
|
|
|
|
* failure, @wait will be implicitly turned on.
|
|
|
|
*
|
|
|
|
* You must not call this function with disabled interrupts or from a
|
|
|
|
* hardware interrupt handler or from a bottom half handler.
|
|
|
|
*/
|
2008-06-06 03:18:06 -06:00
|
|
|
int smp_call_function(void (*func)(void *), void *info, int wait)
|
2008-06-26 03:21:34 -06:00
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
preempt_disable();
|
|
|
|
ret = smp_call_function_mask(cpu_online_map, func, info, wait);
|
|
|
|
preempt_enable();
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(smp_call_function);
|
|
|
|
|
|
|
|
void ipi_call_lock(void)
|
|
|
|
{
|
|
|
|
spin_lock(&call_function_lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ipi_call_unlock(void)
|
|
|
|
{
|
|
|
|
spin_unlock(&call_function_lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ipi_call_lock_irq(void)
|
|
|
|
{
|
|
|
|
spin_lock_irq(&call_function_lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
void ipi_call_unlock_irq(void)
|
|
|
|
{
|
|
|
|
spin_unlock_irq(&call_function_lock);
|
|
|
|
}
|