From d3fcd7360338358aa0036bec6d2cf0e37a0ca624 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Thu, 3 Aug 2023 11:12:33 -0600 Subject: [PATCH] PCI: Fix runtime PM race with PME polling Testing that a device is not currently in a low power state provides no guarantees that the device is not imminently transitioning to such a state. Increment the PM usage counter before accessing the device. Since we don't wish to wake the device for PME polling, do so only if the device is already active by using pm_runtime_get_if_active(). Link: https://lore.kernel.org/r/20230803171233.3810944-3-alex.williamson@redhat.com Signed-off-by: Alex Williamson Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 60230da..bc266f2 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2415,10 +2415,13 @@ static void pci_pme_list_scan(struct work_struct *work) mutex_lock(&pci_pme_list_mutex); list_for_each_entry_safe(pme_dev, n, &pci_pme_list, list) { - if (pme_dev->dev->pme_poll) { - struct pci_dev *bridge; + struct pci_dev *pdev = pme_dev->dev; + + if (pdev->pme_poll) { + struct pci_dev *bridge = pdev->bus->self; + struct device *dev = &pdev->dev; + int pm_status; - bridge = pme_dev->dev->bus->self; /* * If bridge is in low power state, the * configuration space of subordinate devices @@ -2426,14 +2429,20 @@ static void pci_pme_list_scan(struct work_struct *work) */ if (bridge && bridge->current_state != PCI_D0) continue; + /* - * If the device is in D3cold it should not be - * polled either. + * If the device is in a low power state it + * should not be polled either. */ - if (pme_dev->dev->current_state == PCI_D3cold) + pm_status = pm_runtime_get_if_active(dev, true); + if (!pm_status) continue; - pci_pme_wakeup(pme_dev->dev, NULL); + if (pdev->current_state != PCI_D3cold) + pci_pme_wakeup(pdev, NULL); + + if (pm_status > 0) + pm_runtime_put(dev); } else { list_del(&pme_dev->list); kfree(pme_dev); -- 2.7.4