netdev - RE: ixgbe: pci_get_device() call without counterpart call of pci_dev

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Message-ID: <C5551D9AAB213A418B7FD5E4A6F30A072D5F4365@ORSMSX106.amr.corp.intel.com>
Date:	Mon, 10 Dec 2012 18:24:03 +0000
From:	"Rose, Gregory V" <gregory.v.rose@...el.com>
To:	"Kirsher, Jeffrey T" <jeffrey.t.kirsher@...el.com>,
	Elena Gurevich <elena.gurevich@...anetworks.com>
CC:	netdev <netdev@...r.kernel.org>,
	"e1000-devel@...ts.sourceforge.net" 
	<e1000-devel@...ts.sourceforge.net>,
	"Skidmore, Donald C" <donald.c.skidmore@...el.com>
Subject: RE: ixgbe:  pci_get_device() call without counterpart call of
 pci_dev_put()

> -----Original Message-----
> From: Jeff Kirsher [mailto:tarbal@...il.com]
> Sent: Sunday, December 09, 2012 11:18 PM
> To: Elena Gurevich
> Cc: netdev; e1000-devel@...ts.sourceforge.net; Rose, Gregory V; Skidmore,
> Donald C
> Subject: Re: ixgbe: pci_get_device() call without counterpart call of
> pci_dev_put()
> 
> On 12/09/2012 01:47 AM, Elena Gurevich wrote:
> > Hi all,
> > I am pioneer in linux device drivers here and using Intel 82599 NIC as
> > reference model, During investigation to drivers sources I found the
> > suspicious code:
> >
> > Is code sequence (1)   and (2) the possible device reference count
> leakage
> > ???
> >
> >
> > Thanks a lot in advance
> > Lena
> >
> > --------snipped from ixgbe_main.c  file function
> > ixgbe_io_error_detected()
> > -----------
> >
> > . . .
> > 		/* Find the pci device of the offending VF */
> > 		vfdev = pci_get_device(PCI_VENDOR_ID_INTEL, device_id, NULL);
> > 		while (vfdev) {
> > 			if (vfdev->devfn == (req_id & 0xFF))
> > 				break;
> > <------------------------------      (1) leaves the loop with successful
> get
> > call  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> >
> > 			vfdev = pci_get_device(PCI_VENDOR_ID_INTEL,
> > 					       device_id, vfdev);
> > 		}
> > 		/*
> > 		 * There's a slim chance the VF could have been hot plugged,
> > 		 * so if it is no longer present we don't need to issue the
> > 		 * VFLR.  Just clean up the AER in that case.
> > 		 */
> > 		if (vfdev) {
> > 			e_dev_err("Issuing VFLR to VF %d\n", vf);
> > 			pci_write_config_dword(vfdev, 0xA8, 0x00008000);
> > 		}
> >
> > 		pci_cleanup_aer_uncorrect_error_status(pdev);
> > 	}
> >
> > 	/*
> > 	 * Even though the error may have occurred on the other port
> > 	 * we still need to increment the vf error reference count for
> > 	 * both ports because the I/O resume function will be called
> > 	 * for both of them.
> > 	 */
> > 	adapter->vferr_refcount++;
> >
> > 	return PCI_ERS_RESULT_RECOVERED;
> > <--------------------------------------------  (2) leaves the function
> > without put call !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> > ----------------------------------  snipped
> > -----------------------------------
> >
> Added Greg Rose (ixgbevf maintainer) & Don Skidmore (ixgbe maintainer)
> 
> Since the code you have questions about is dealing with the vf, Greg will
> most likely be able to shed some light to your questions.

That's a bug.  I'll generate a patch to add the necessary pci_dev_put().

- Greg