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

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