[+cc Johan, Kai-Heng] On Mon, Jan 22, 2024 at 05:43:09PM +0300, Dan Carpenter wrote: > Hello Bjorn Helgaas, > > The patch f93e71aea6c6: "Revert "PCI/ASPM: Remove > pcie_aspm_pm_state_change()"" from Jan 1, 2024 (linux-next), leads to > the following Smatch static checker warning: > > drivers/pci/pcie/aspm.c:1017 pcie_aspm_pm_state_change() > warn: sleeping in atomic context Thanks Dan, this is probably related to the lockdep issue Johan reported here: https://lore.kernel.org/r/ZZu0qx2cmn7IwTyQ@xxxxxxxxxxxxxxxxxxxx This is definitely an open issue that should be resolved. Bjorn > drivers/pci/pcie/aspm.c > 1007 void pcie_aspm_pm_state_change(struct pci_dev *pdev) > 1008 { > 1009 struct pcie_link_state *link = pdev->link_state; > 1010 > 1011 if (aspm_disabled || !link) > 1012 return; > 1013 /* > 1014 * Devices changed PM state, we should recheck if latency > 1015 * meets all functions' requirement > 1016 */ > --> 1017 down_read(&pci_bus_sem); > > This is a revert from a patch from 2022 which was before I had written > this "sleeping in atomic" static checker thing. > > 1018 mutex_lock(&aspm_lock); > 1019 pcie_update_aspm_capable(link->root); > 1020 pcie_config_aspm_path(link); > 1021 mutex_unlock(&aspm_lock); > 1022 up_read(&pci_bus_sem); > 1023 } > > The call trees that Smatch is complaining about are: > > vortex_boomerang_interrupt() <- disables preempt > -> _vortex_interrupt() > -> _boomerang_interrupt() > -> vortex_error() > -> vortex_up() > velocity_suspend() <- disables preempt > -> velocity_set_power_state() > -> pci_set_power_state() > -> pci_set_low_power_state() > -> pcie_aspm_pm_state_change() > > So what Smatch is saying is the vortex_boomerang_interrupt() and > velocity_suspend() hold spin locks and then set the power state. The > call trees are quite long so I'm not really able to be sure if this is > a false positive or not... I wish this warning were more useful. > > These emails are a one time thing. Just reply if it's a false positive > and I'll note it down. Otherwise feel free to ignore it. > > regards, > dan carpenter
