Hi, While working with the PCI endpoint subsystem, I stumbled upon the sleeping in atomic context bug during CORE_INIT phase. The issue seems to be due to the usage of "epc lock" (mutex) in functions such as set_msi, set_msix, write_header, etc... These functions are supposed to be used in the atomic notifier chain by the CORE_INIT notifier. While using the lock is necessary in these functions as pci_epc_create() would've been called, I see two possible workarounds: 1. Using non-atomic notifier chains such as blocking or raw. 2. Modifying the EPF drivers to use workqueue in CORE_INIT notifier chain. But this has the implication of missing the workqueue execution before hitting other PCI events as there might be a delay in scheduling the work item. I prefer 1st option but I'd like to hear other ideas also. Thanks, Mani
