linux-kernel - Re: [3.11.4] Thunderbolt/PCI unplug oops in pci_pme_list

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Date:	Wed, 20 Nov 2013 09:14:33 +0800
From:	Yijing Wang <wangyijing@...wei.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
CC:	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Andreas Noever <andreas.noever@...il.com>,
	"Matthew Garrett" <mjg59@...f.ucam.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [3.11.4] Thunderbolt/PCI unplug oops in pci_pme_list_scan

>>> [bhelgaas: changelog, tag for stable]
>>> Reported-by: David Bulkow <David.Bulkow@...atus.com>
>>> Reported-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
>>> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
>>> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
>>> CC: stable@...r.kernel.org	# v2.6.32+
>>
>> Hi Bjorn,
>>    This issue in X86 seems to be introduced after commit 928bea9 "PCI: Delay enabling bridges until they're needed"
>> So this patch needs to back port to 2.6.32+ ?
> 
> 928bea9 might have made it more visible, but the underlying problem is that
> we enable the device once in the probe path, and disable it twice in the
> remove path.  That problem exists in 2.6.32.61:
> 
>   pcie_portdrv_probe                # .probe() method
>     pcie_port_device_register
>       pci_enable_device             <-- enable
> 
>   pcie_portdrv_remove               # .remove() method
>     pcie_port_device_remove
>       pci_disable_device            <-- disable #1
>     pci_disable_device              <-- disable #2

During assign unassigned resources, we also enable the port device,

fs_initcall(pcibios_assign_resources);
  pci_assign_unassigned_resources;
    pci_enable_bridges()
      pci_enable_device()


So I think before the commit 928bea9 , the pci bridge device enable and disable is symmetrical.
After the commit 928bea9, we only enable bridge once, but still remove twice.

Thanks!
Yijing.


-- 
Thanks!
Yijing

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