Re: Latest bk kernel does not properly free PCI IO & MEM allocations

[Greg KH <greg@kroah.com>]

On Wed, Mar 09, 2005 at 01:38:33PM -0500, Prarit Bhargava wrote:
> 
> 
> Hello all,
> 
> I noticed this in testing of a hotplug driver I've written for SGI Altix 
> hardware.
> 
> If you cat /proc/iomem and check lspci after removing a device via hotplug:
> 
> [root@cranberry3 linux-2.6.9-hotplug]# lspci
> 01:01.0 Co-processor: Silicon Graphics, Inc. IOC4 I/O controller (rev 4f)
> 01:03.0 SCSI storage controller: QLogic Corp. ISP12160 Dual Channel Ultra3 
> SCSI Processor (rev 06)
> 01:04.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5701 Gigabit 
> Ethernet (rev 15)
> 03:02.0 ATM network controller: FORE Systems Inc ForeRunnerHE ATM Adapter
> 04:01.0 SCSI storage controller: QLogic Corp. QLA2200 64-bit Fibre Channel 
> Adapter (rev 05)
> [root@cranberry3 linux-2.6.9-hotplug]# cat /proc/iomem 
> c00004080c200000-c00004080c2fffff : 0000:01:01.0
> c00004080f400000-c00004080f4fffff : 0000:03:02.0
> c00004080fe00000-c00004080fe00fff : 0000:04:01.0
> c00004080fe01000-c00004080fe01fff : 0000:04:02.0
>  00220000-0023ffff : 0000:04:01.0
> 
> There are still allocations listed for device 04:02.0 even though it has 
> been
> removed from the system.
> 
> I tracked down the issue to the following:
> 
> When pci_remove_bus_device is called on the device in the slot (should be a 
> safe thing to do) both the pci_driver remove function for a device and the 
> function pci_free_resources are called.
> 
> In the case of the QLA2x00 driver, the driver's remove function calls
> pci_release_regions.  This function releases the IO & MEM allocs for the pci
> device and kfree's them.
> 
> As previously mentioned, pci_free_resources is called.  This function 
> attempts to use and free IO & MEM allocs for the pci device.

Where does it attempt to use it?  I see a loop to free the resources,
not anything else.

Also, if you enable slab debugging, does this always occur?

And, this should be brought up on the linux-pci mailing list, not the
hotplug list.

thanks,

greg k-h


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