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Commit 75135da0 authored by Jean Delvare's avatar Jean Delvare Committed by Borislav Petkov
Browse files

i7300_edac: Fix device reference count 



pci_get_device() decrements the reference count of "from" (last
argument) so when we break off the loop successfully we have only one
device reference - and we don't know which device we have. If we want
a reference to each device, we must take them explicitly and let
the pci_get_device() walk complete to avoid duplicate references.

This is serious, as over-putting device references will cause
the device to eventually disappear. Without this fix, the kernel
crashes after a few insmod/rmmod cycles.

Tested on an Intel S7000FC4UR system with a 7300 chipset.

Signed-off-by: default avatarJean Delvare <jdelvare@suse.de>
Link: http://lkml.kernel.org/r/20140224111656.09bbb7ed@endymion.delvare


Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Doug Thompson <dougthompson@xmission.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
parent c0f5eeed

drivers/edac/i7300_edac.c

+20 −18
Original line number Diff line number Diff line
@@ -943,33 +943,35 @@ static int i7300_get_devices(struct mem_ctl_info *mci) 


	/* Attempt to 'get' the MCH register we want */

	pdev = NULL;

	while (!pvt->pci_dev_16_1_fsb_addr_map ||

	       !pvt->pci_dev_16_2_fsb_err_regs) {

		pdev = pci_get_device(PCI_VENDOR_ID_INTEL,

				      PCI_DEVICE_ID_INTEL_I7300_MCH_ERR, pdev);

		if (!pdev) {

			/* End of list, leave */

			i7300_printk(KERN_ERR,

				"'system address,Process Bus' "

				"device not found:"

				"vendor 0x%x device 0x%x ERR funcs "

				"(broken BIOS?)\n",

				PCI_VENDOR_ID_INTEL,

				PCI_DEVICE_ID_INTEL_I7300_MCH_ERR);

			goto error;

		}



	while ((pdev = pci_get_device(PCI_VENDOR_ID_INTEL,

				      PCI_DEVICE_ID_INTEL_I7300_MCH_ERR,

				      pdev))) {

		/* Store device 16 funcs 1 and 2 */

		switch (PCI_FUNC(pdev->devfn)) {

		case 1:

			pvt->pci_dev_16_1_fsb_addr_map = pdev;

			if (!pvt->pci_dev_16_1_fsb_addr_map)

				pvt->pci_dev_16_1_fsb_addr_map =

							pci_dev_get(pdev);

			break;

		case 2:

			pvt->pci_dev_16_2_fsb_err_regs = pdev;

			if (!pvt->pci_dev_16_2_fsb_err_regs)

				pvt->pci_dev_16_2_fsb_err_regs =

							pci_dev_get(pdev);

			break;

		}

	}



	if (!pvt->pci_dev_16_1_fsb_addr_map ||

	    !pvt->pci_dev_16_2_fsb_err_regs) {

		/* At least one device was not found */

		i7300_printk(KERN_ERR,

			"'system address,Process Bus' device not found:"

			"vendor 0x%x device 0x%x ERR funcs (broken BIOS?)\n",

			PCI_VENDOR_ID_INTEL,

			PCI_DEVICE_ID_INTEL_I7300_MCH_ERR);

		goto error;

	}



	edac_dbg(1, "System Address, processor bus- PCI Bus ID: %s  %x:%x\n",

		 pci_name(pvt->pci_dev_16_0_fsb_ctlr),

		 pvt->pci_dev_16_0_fsb_ctlr->vendor,