Re: [PATCH 3/4] pci aer: fix deadlock in do_recovery

[Sinan Kaya]

On 9/27/2017 5:42 PM, Govindarajulu Varadarajan wrote:
> CPU0					CPU1
> ---------------------------------------------------------------------
> __driver_attach()
> device_lock(&dev->mutex) <--- device mutex lock here
> driver_probe_device()
> pci_enable_sriov()
> pci_iov_add_virtfn()
> pci_device_add()
> 					aer_isr()		<--- pci aer error
> 					do_recovery()
> 					broadcast_error_message()
> 					pci_walk_bus()
> 					down_read(&pci_bus_sem) <--- rd sem

How about releasing the device_lock here on CPU0? or in other words keep
device_lock as short as possible?

> down_write(&pci_bus_sem) <-- stuck on wr sem
> 					report_error_detected()
> 					device_lock(&dev->mutex)<--- DEAD LOCK


-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.