From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prarit Bhargava Date: Wed, 09 Mar 2005 18:38:33 +0000 Subject: Latest bk kernel does not properly free PCI IO & MEM allocations Message-Id: <422F42A9.7050009@sgi.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org 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. This may (about 5% of the time) causes an oops, ie) this is a critical issue for anyone using hotplug. This raises the following question -- should a driver be cleaning up resources or should PCI? P. ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel