From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prarit Bhargava Date: Thu, 10 Mar 2005 15:07:12 +0000 Subject: Re: Latest bk kernel does not properly free PCI IO & MEM allocations Message-Id: <423062A0.4070509@sgi.com> MIME-Version: 1 Content-Type: multipart/mixed; boundary="------------000502040308040800040305" List-Id: References: <422F42A9.7050009@sgi.com> In-Reply-To: <422F42A9.7050009@sgi.com> To: linux-hotplug@vger.kernel.org This is a multi-part message in MIME format. --------------000502040308040800040305 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit The following patch reproduces the oops 100% of the time by doing the following. Boot machine. Load Hotplug driver (if not already loaded) Disable Slot that has MEM and IO allocations cat /proc/iomem <--- leads to oops. P. 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. > > 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_id=6595&alloc_id=14396&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 > --------------000502040308040800040305 Content-Type: text/x-patch; name="repro.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="repro.patch" --- kernel/resource.c.orig 2005-03-10 14:57:58.317008676 -0500 +++ kernel/resource.c 2005-03-10 14:58:02.310172689 -0500 @@ -495,20 +495,21 @@ break; if (res->start <= start && res->end >= end) { if (!(res->flags & IORESOURCE_BUSY)) { p = &res->child; continue; } if (res->start != start || res->end != end) break; *p = res->sibling; write_unlock(&resource_lock); + memset(res, 0, sizeof(*res)); kfree(res); return; } p = &res->sibling; } write_unlock(&resource_lock); printk(KERN_WARNING "Trying to free nonexistent resource <%08lx-%08lx>\n", start, end); } --------------000502040308040800040305-- ------------------------------------------------------- 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_id=6595&alloc_id=14396&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