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From: Sinan Kaya <okaya@codeaurora.org>
To: Govindarajulu Varadarajan <gvaradar@cisco.com>,
	benve@cisco.com, bhelgaas@google.com, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, jlbec@evilplan.org, hch@lst.de,
	mingo@redhat.com, peterz@infradead.org
Subject: Re: [PATCH 3/4] pci aer: fix deadlock in do_recovery
Date: Thu, 28 Sep 2017 12:47:45 -0400	[thread overview]
Message-ID: <2dc437fe-2ab4-23e3-44f3-f06feaf88d86@codeaurora.org> (raw)
In-Reply-To: <20170927214220.41216-4-gvaradar@cisco.com>

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.

  reply	other threads:[~2017-09-28 16:47 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-27 21:42 [PATCH 0/4] pci aer: fix deadlock in do_recovery Govindarajulu Varadarajan
2017-09-27 21:42 ` [PATCH 1/4] pci: introduce __pci_walk_bus for caller with pci_bus_sem held Govindarajulu Varadarajan
2017-09-28 16:12   ` Sinan Kaya
2017-09-28 23:52     ` Govindarajulu Varadarajan
2017-09-27 21:42 ` [PATCH 2/4] pci: code refactor pci_bus_lock/unlock/trylock Govindarajulu Varadarajan
2017-09-27 21:42 ` [PATCH 3/4] pci aer: fix deadlock in do_recovery Govindarajulu Varadarajan
2017-09-28 16:47   ` Sinan Kaya [this message]
2017-09-28 23:46     ` Govindarajulu Varadarajan
2017-09-29 13:32       ` Sinan Kaya
2017-09-30  6:00         ` Govindarajulu Varadarajan
2017-09-27 21:42 ` [PATCH 4/4] lockdep: make MAX_LOCK_DEPTH configurable from Kconfig Govindarajulu Varadarajan
2017-09-28  9:26   ` Peter Zijlstra
2017-09-28 23:51     ` Govindarajulu Varadarajan
2017-09-29 16:23       ` Bjorn Helgaas
2017-09-30  6:03         ` Govindarajulu Varadarajan

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