From 6c50384ef8b94a527445e3694ae6549e1f15d859 Mon Sep 17 00:00:00 2001 From: Yicong Yang Date: Wed, 21 Jun 2023 17:28:04 +0800 Subject: [PATCH] hwtracing: hisi_ptt: Fix potential sleep in atomic context We're using pci_irq_vector() to obtain the interrupt number and then bind it to the CPU start perf under the protection of spinlock in pmu::start(). pci_irq_vector() might sleep since [1] because it will call msi_domain_get_virq() to get the MSI interrupt number and it needs to acquire dev->msi.data->mutex. Getting a mutex will sleep on contention. So use pci_irq_vector() in an atomic context is problematic. This patch cached the interrupt number in the probe() and uses the cached data instead to avoid potential sleep. [1] commit 82ff8e6b78fc ("PCI/MSI: Use msi_get_virq() in pci_get_vector()") Fixes: ff0de066b463 ("hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device") Reviewed-by: Jonathan Cameron Signed-off-by: Yicong Yang Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20230621092804.15120-6-yangyicong@huawei.com --- drivers/hwtracing/ptt/hisi_ptt.c | 12 +++++------- drivers/hwtracing/ptt/hisi_ptt.h | 2 ++ 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c index 103fb6b..ba081b6 100644 --- a/drivers/hwtracing/ptt/hisi_ptt.c +++ b/drivers/hwtracing/ptt/hisi_ptt.c @@ -341,13 +341,13 @@ static int hisi_ptt_register_irq(struct hisi_ptt *hisi_ptt) if (ret < 0) return ret; - ret = devm_request_threaded_irq(&pdev->dev, - pci_irq_vector(pdev, HISI_PTT_TRACE_DMA_IRQ), + hisi_ptt->trace_irq = pci_irq_vector(pdev, HISI_PTT_TRACE_DMA_IRQ); + ret = devm_request_threaded_irq(&pdev->dev, hisi_ptt->trace_irq, NULL, hisi_ptt_isr, 0, DRV_NAME, hisi_ptt); if (ret) { pci_err(pdev, "failed to request irq %d, ret = %d\n", - pci_irq_vector(pdev, HISI_PTT_TRACE_DMA_IRQ), ret); + hisi_ptt->trace_irq, ret); return ret; } @@ -1098,8 +1098,7 @@ static void hisi_ptt_pmu_start(struct perf_event *event, int flags) * core in event_function_local(). If CPU passed is offline we'll fail * here, just log it since we can do nothing here. */ - ret = irq_set_affinity(pci_irq_vector(hisi_ptt->pdev, HISI_PTT_TRACE_DMA_IRQ), - cpumask_of(cpu)); + ret = irq_set_affinity(hisi_ptt->trace_irq, cpumask_of(cpu)); if (ret) dev_warn(dev, "failed to set the affinity of trace interrupt\n"); @@ -1394,8 +1393,7 @@ static int hisi_ptt_cpu_teardown(unsigned int cpu, struct hlist_node *node) * Also make sure the interrupt bind to the migrated CPU as well. Warn * the user on failure here. */ - if (irq_set_affinity(pci_irq_vector(hisi_ptt->pdev, HISI_PTT_TRACE_DMA_IRQ), - cpumask_of(target))) + if (irq_set_affinity(hisi_ptt->trace_irq, cpumask_of(target))) dev_warn(dev, "failed to set the affinity of trace interrupt\n"); hisi_ptt->trace_ctrl.on_cpu = target; diff --git a/drivers/hwtracing/ptt/hisi_ptt.h b/drivers/hwtracing/ptt/hisi_ptt.h index 164012d..e17f045 100644 --- a/drivers/hwtracing/ptt/hisi_ptt.h +++ b/drivers/hwtracing/ptt/hisi_ptt.h @@ -201,6 +201,7 @@ struct hisi_ptt_pmu_buf { * @pdev: pci_dev of this PTT device * @tune_lock: lock to serialize the tune process * @pmu_lock: lock to serialize the perf process + * @trace_irq: interrupt number used by trace * @upper_bdf: the upper BDF range of the PCI devices managed by this PTT device * @lower_bdf: the lower BDF range of the PCI devices managed by this PTT device * @port_filters: the filter list of root ports @@ -221,6 +222,7 @@ struct hisi_ptt { struct pci_dev *pdev; struct mutex tune_lock; spinlock_t pmu_lock; + int trace_irq; u32 upper_bdf; u32 lower_bdf; -- 2.7.4