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iommu/iova: avoid softlockup in fq_flush_timeout 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8ZE0I
CVE: NA

--------------------------------

There is a softlockup undering cpu pressure test.
...
pc : _raw_spin_unlock_irqrestore+0x14/0x78
lr : fq_flush_timeout+0x94/0x118
...
Call trace:
 _raw_spin_unlock_irqrestore+0x14/0x78
 call_timer_fn+0x3c/0x1d0
 expire_timers+0xcc/0x190
 run_timer_softirq+0xfc/0x268
 __do_softirq+0x128/0x3dc
 ____do_softirq+0x18/0x30
 call_on_irq_stack+0x24/0x30
 do_softirq_own_stack+0x24/0x38
 irq_exit_rcu+0xc0/0xe8
 el1_interrupt+0x48/0xc0
 el1h_64_irq_handler+0x18/0x28
 el1h_64_irq+0x78/0x80
 __schedule+0xf28/0x12a0
 schedule+0x3c/0x108
 schedule_timeout+0xa0/0x1d0
 pktgen_thread_worker+0x1180/0x15d0
 kthread+0x120/0x130
 ret_from_fork+0x10/0x20

This is because the timer callback fq_flush_timeout may run more than
10ms, and timer may be processed continuously in the softirq so trigger
softlockup. We can use work to deal with fq_ring_free for each cpu which
may take long time, that to avoid triggering softlockup.

Signed-off-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Zhang Zekun <zhangzekun11@huawei.com>
Signed-off-by: Zihao Xue <xuezihao@huawei.com>
This commit is contained in:
Zhang Zekun 2024-03-19 14:12:34 +08:00 committed by Jianping Liu
parent c441d1bac9
commit a4ae0ae208
1 changed files with 20 additions and 7 deletions
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27
drivers/iommu/dma-iommu.c
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@ -83,6 +83,8 @@ struct iommu_dma_cookie {
/* Options for dma-iommu use */
struct iommu_dma_options options;
struct mutex mutex;
struct work_struct free_iova_work;
};
static DEFINE_STATIC_KEY_FALSE(iommu_deferred_attach_enabled);
@ -179,17 +181,11 @@ static void fq_flush_iotlb(struct iommu_dma_cookie *cookie)
static void fq_flush_timeout(struct timer_list *t)
{
struct iommu_dma_cookie *cookie = from_timer(cookie, t, fq_timer);
int cpu;
atomic_set(&cookie->fq_timer_on, 0);
fq_flush_iotlb(cookie);
if (cookie->options.qt == IOMMU_DMA_OPTS_SINGLE_QUEUE) {
fq_ring_free(cookie, cookie->single_fq);
} else {
for_each_possible_cpu(cpu)
fq_ring_free(cookie, per_cpu_ptr(cookie->percpu_fq, cpu));
}
schedule_work(&cookie->free_iova_work);
}
static void queue_iova(struct iommu_dma_cookie *cookie,
@ -274,6 +270,7 @@ static void iommu_dma_free_fq(struct iommu_dma_cookie *cookie)
return;
del_timer_sync(&cookie->fq_timer);
flush_work(&cookie->free_iova_work);
if (cookie->options.qt == IOMMU_DMA_OPTS_SINGLE_QUEUE)
iommu_dma_free_fq_single(cookie->single_fq);
else
@ -321,6 +318,21 @@ static int iommu_dma_init_fq_percpu(struct iommu_dma_cookie *cookie)
return 0;
}
static void free_iova_work_func(struct work_struct *work)
{
struct iommu_dma_cookie *cookie;
int cpu;
cookie = container_of(work, struct iommu_dma_cookie, free_iova_work);
if (cookie->options.qt == IOMMU_DMA_OPTS_SINGLE_QUEUE) {
fq_ring_free(cookie, cookie->single_fq);
} else {
for_each_possible_cpu(cpu)
fq_ring_free(cookie, per_cpu_ptr(cookie->percpu_fq, cpu));
}
}
/* sysfs updates are serialised by the mutex of the group owning @domain */
int iommu_dma_init_fq(struct iommu_domain *domain)
{
@ -343,6 +355,7 @@ int iommu_dma_init_fq(struct iommu_domain *domain)
return -ENOMEM;
}
INIT_WORK(&cookie->free_iova_work, free_iova_work_func);
timer_setup(&cookie->fq_timer, fq_flush_timeout, 0);
atomic_set(&cookie->fq_timer_on, 0);
/*