diff mbox series

misc: hpilo: Fix use after free bug in ilo_remove due to race condition with ilo_open

Message ID 20230417165246.467723-1-zyytlz.wz@163.com
State New
Headers
Series misc: hpilo: Fix use after free bug in ilo_remove due to race condition with ilo_open |

Commit Message

Zheng Wang April 17, 2023, 4:52 p.m. UTC 
  A race condition may occur if the user physically removes the ilo device 
while calling ilo_open.

If we remove the driver which will call ilo_remove to make cleanup, there 
is no guarantee to make sure there's no more ilo_open invoking.

The possible sequence is as follows:

Fix it by adding a refcount check to ilo_remove() function to free the 
"ilo_hwinfo " structure after the last file is closed.

CPU0                  CPU1

                    |ilo_open
ilo_remove          |
kfree(ilo_hw)       |
//free	            |
                    |hw = container_of(ip->i_cdev,
	   	     |struct ilo_hwinfo, cdev);
                    |hw->ccb_alloc[slot]
                    |//use
Fixes: 89bcb05d9bbf ("HP iLO driver")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
 drivers/misc/hpilo.c | 16 +++++++++++++++-
 drivers/misc/hpilo.h |  1 +
 2 files changed, 16 insertions(+), 1 deletion(-)

Comments

Greg KH April 17, 2023, 5:43 p.m. UTC | #1 
On Tue, Apr 18, 2023 at 12:52:46AM +0800, Zheng Wang wrote:
> --- a/drivers/misc/hpilo.h
> +++ b/drivers/misc/hpilo.h
> @@ -62,6 +62,7 @@ struct ilo_hwinfo {
>  	spinlock_t fifo_lock;
>  
>  	struct cdev cdev;
> +	struct kref refcnt;

You now have 2 different structures doing reference counting logic on
the same structure.  That's just not ok at all, and is totally broken.

greg k-h
Zheng Hacker April 19, 2023, 5:29 a.m. UTC | #2 
Greg KH <gregkh@linuxfoundation.org> 于2023年4月18日周二 01:43写道：
>
> On Tue, Apr 18, 2023 at 12:52:46AM +0800, Zheng Wang wrote:
> > --- a/drivers/misc/hpilo.h
> > +++ b/drivers/misc/hpilo.h
> > @@ -62,6 +62,7 @@ struct ilo_hwinfo {
> >       spinlock_t fifo_lock;
> >
> >       struct cdev cdev;
> > +     struct kref refcnt;
>
> You now have 2 different structures doing reference counting logic on
> the same structure.  That's just not ok at all, and is totally broken.
>

Thanks for your reply. I'll look into it and figure out effective fix.

Best regards,
Zheng

> greg k-h
Dan Carpenter May 2, 2023, 11:46 a.m. UTC | #3 
Hi Zheng,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Zheng-Wang/misc-hpilo-Fix-use-after-free-bug-in-ilo_remove-due-to-race-condition-with-ilo_open/20230418-005502
base:   char-misc/char-misc-testing
patch link:    https://lore.kernel.org/r/20230417165246.467723-1-zyytlz.wz%40163.com
patch subject: [PATCH] misc: hpilo: Fix use after free bug in ilo_remove due  to race condition with ilo_open
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20230430/202304300909.ALHN6Vry-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Link: https://lore.kernel.org/r/202304300909.ALHN6Vry-lkp@intel.com/

smatch warnings:
drivers/misc/hpilo.c:755 ilo_delete() warn: can 'ilo_hw' even be NULL?

vim +/ilo_hw +755 drivers/misc/hpilo.c

13a22f45e6cb1e Zheng Wang      2023-04-18  749  static void ilo_delete(struct kref *kref)
13a22f45e6cb1e Zheng Wang      2023-04-18  750  {
13a22f45e6cb1e Zheng Wang      2023-04-18  751  	int i, minor;
13a22f45e6cb1e Zheng Wang      2023-04-18  752  	struct ilo_hwinfo *ilo_hw = container_of(kref, struct ilo_hwinfo, refcnt);
13a22f45e6cb1e Zheng Wang      2023-04-18  753  	struct pci_dev *pdev = ilo_hw->ilo_dev;
89bcb05d9bbf8b David Altobelli 2008-07-02  754  
ebf1b764aa5cb3 Mark Rusk       2012-11-06 @755  	if (!ilo_hw)
                                                            ^^^^^^^

->refcnt member isn't the first struct member so this NULL check
doesn't make sense.  Generally checking container_of() is ugly.  Some
people do it and add BUILD_BUG_ON() to ensure that they're checking the
first struct member but really it's best to avoid that if possible.

ebf1b764aa5cb3 Mark Rusk       2012-11-06  756  		return;
ebf1b764aa5cb3 Mark Rusk       2012-11-06  757  
89bcb05d9bbf8b David Altobelli 2008-07-02  758  	clear_device(ilo_hw);
89bcb05d9bbf8b David Altobelli 2008-07-02  759  
89bcb05d9bbf8b David Altobelli 2008-07-02  760  	minor = MINOR(ilo_hw->cdev.dev);
98dcd59dd063dd Camuso, Tony    2012-06-10  761  	for (i = minor; i < minor + max_ccb; i++)
89bcb05d9bbf8b David Altobelli 2008-07-02  762  		device_destroy(ilo_class, MKDEV(ilo_major, i));
89bcb05d9bbf8b David Altobelli 2008-07-02  763  
89bcb05d9bbf8b David Altobelli 2008-07-02  764  	cdev_del(&ilo_hw->cdev);
9f7048412163d8 David Altobelli 2009-08-17  765  	ilo_disable_interrupts(ilo_hw);
9f7048412163d8 David Altobelli 2009-08-17  766  	free_irq(pdev->irq, ilo_hw);
89bcb05d9bbf8b David Altobelli 2008-07-02  767  	ilo_unmap_device(pdev, ilo_hw);
89bcb05d9bbf8b David Altobelli 2008-07-02  768  	pci_release_regions(pdev);
bcdee04ea7ae04 Jiri Slaby      2012-09-13  769  	/*
bcdee04ea7ae04 Jiri Slaby      2012-09-13  770  	 * pci_disable_device(pdev) used to be here. But this PCI device has
bcdee04ea7ae04 Jiri Slaby      2012-09-13  771  	 * two functions with interrupt lines connected to a single pin. The
bcdee04ea7ae04 Jiri Slaby      2012-09-13  772  	 * other one is a USB host controller. So when we disable the PIN here
bcdee04ea7ae04 Jiri Slaby      2012-09-13  773  	 * e.g. by rmmod hpilo, the controller stops working. It is because
bcdee04ea7ae04 Jiri Slaby      2012-09-13  774  	 * the interrupt link is disabled in ACPI since it is not refcounted
bcdee04ea7ae04 Jiri Slaby      2012-09-13  775  	 * yet. See acpi_pci_link_free_irq called from acpi_pci_irq_disable.
bcdee04ea7ae04 Jiri Slaby      2012-09-13  776  	 */
89bcb05d9bbf8b David Altobelli 2008-07-02  777  	kfree(ilo_hw);
98dcd59dd063dd Camuso, Tony    2012-06-10  778  	ilo_hwdev[(minor / max_ccb)] = 0;
89bcb05d9bbf8b David Altobelli 2008-07-02  779  }
Zheng Hacker May 5, 2023, 4:01 a.m. UTC | #4 
Dear Dan,

Thanks for your reply. I'm not so familiar with the code here. Is the
warning says we should check ilo_hw to see if it's not NULL?

Best regards,
Zheng

Dan Carpenter <dan.carpenter@linaro.org> 于2023年5月2日周二 19:46写道：
>
> Hi Zheng,
>
> kernel test robot noticed the following build warnings:
>
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Zheng-Wang/misc-hpilo-Fix-use-after-free-bug-in-ilo_remove-due-to-race-condition-with-ilo_open/20230418-005502
> base:   char-misc/char-misc-testing
> patch link:    https://lore.kernel.org/r/20230417165246.467723-1-zyytlz.wz%40163.com
> patch subject: [PATCH] misc: hpilo: Fix use after free bug in ilo_remove due  to race condition with ilo_open
> config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20230430/202304300909.ALHN6Vry-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
>
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <error27@gmail.com>
> | Link: https://lore.kernel.org/r/202304300909.ALHN6Vry-lkp@intel.com/
>
> smatch warnings:
> drivers/misc/hpilo.c:755 ilo_delete() warn: can 'ilo_hw' even be NULL?
>
> vim +/ilo_hw +755 drivers/misc/hpilo.c
>
> 13a22f45e6cb1e Zheng Wang      2023-04-18  749  static void ilo_delete(struct kref *kref)
> 13a22f45e6cb1e Zheng Wang      2023-04-18  750  {
> 13a22f45e6cb1e Zheng Wang      2023-04-18  751          int i, minor;
> 13a22f45e6cb1e Zheng Wang      2023-04-18  752          struct ilo_hwinfo *ilo_hw = container_of(kref, struct ilo_hwinfo, refcnt);
> 13a22f45e6cb1e Zheng Wang      2023-04-18  753          struct pci_dev *pdev = ilo_hw->ilo_dev;
> 89bcb05d9bbf8b David Altobelli 2008-07-02  754
> ebf1b764aa5cb3 Mark Rusk       2012-11-06 @755          if (!ilo_hw)
>                                                             ^^^^^^^
>
> ->refcnt member isn't the first struct member so this NULL check
> doesn't make sense.  Generally checking container_of() is ugly.  Some
> people do it and add BUILD_BUG_ON() to ensure that they're checking the
> first struct member but really it's best to avoid that if possible.
>
> ebf1b764aa5cb3 Mark Rusk       2012-11-06  756                  return;
> ebf1b764aa5cb3 Mark Rusk       2012-11-06  757
> 89bcb05d9bbf8b David Altobelli 2008-07-02  758          clear_device(ilo_hw);
> 89bcb05d9bbf8b David Altobelli 2008-07-02  759
> 89bcb05d9bbf8b David Altobelli 2008-07-02  760          minor = MINOR(ilo_hw->cdev.dev);
> 98dcd59dd063dd Camuso, Tony    2012-06-10  761          for (i = minor; i < minor + max_ccb; i++)
> 89bcb05d9bbf8b David Altobelli 2008-07-02  762                  device_destroy(ilo_class, MKDEV(ilo_major, i));
> 89bcb05d9bbf8b David Altobelli 2008-07-02  763
> 89bcb05d9bbf8b David Altobelli 2008-07-02  764          cdev_del(&ilo_hw->cdev);
> 9f7048412163d8 David Altobelli 2009-08-17  765          ilo_disable_interrupts(ilo_hw);
> 9f7048412163d8 David Altobelli 2009-08-17  766          free_irq(pdev->irq, ilo_hw);
> 89bcb05d9bbf8b David Altobelli 2008-07-02  767          ilo_unmap_device(pdev, ilo_hw);
> 89bcb05d9bbf8b David Altobelli 2008-07-02  768          pci_release_regions(pdev);
> bcdee04ea7ae04 Jiri Slaby      2012-09-13  769          /*
> bcdee04ea7ae04 Jiri Slaby      2012-09-13  770           * pci_disable_device(pdev) used to be here. But this PCI device has
> bcdee04ea7ae04 Jiri Slaby      2012-09-13  771           * two functions with interrupt lines connected to a single pin. The
> bcdee04ea7ae04 Jiri Slaby      2012-09-13  772           * other one is a USB host controller. So when we disable the PIN here
> bcdee04ea7ae04 Jiri Slaby      2012-09-13  773           * e.g. by rmmod hpilo, the controller stops working. It is because
> bcdee04ea7ae04 Jiri Slaby      2012-09-13  774           * the interrupt link is disabled in ACPI since it is not refcounted
> bcdee04ea7ae04 Jiri Slaby      2012-09-13  775           * yet. See acpi_pci_link_free_irq called from acpi_pci_irq_disable.
> bcdee04ea7ae04 Jiri Slaby      2012-09-13  776           */
> 89bcb05d9bbf8b David Altobelli 2008-07-02  777          kfree(ilo_hw);
> 98dcd59dd063dd Camuso, Tony    2012-06-10  778          ilo_hwdev[(minor / max_ccb)] = 0;
> 89bcb05d9bbf8b David Altobelli 2008-07-02  779  }
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests
>
Dan Carpenter May 5, 2023, 7:30 a.m. UTC | #5 
On Fri, May 05, 2023 at 12:01:17PM +0800, Zheng Hacker wrote:
> Dear Dan,
> 
> Thanks for your reply. I'm not so familiar with the code here. Is the
> warning says we should check ilo_hw to see if it's not NULL?
> 

Just delete the NULL check.  It's impossible.

regards,
dan carpenter

> Best regards,
> Zheng
> 
> Dan Carpenter <dan.carpenter@linaro.org> 于2023年5月2日周二 19:46写道：
> >
> > Hi Zheng,
> >
> > kernel test robot noticed the following build warnings:
> >
> > https://git-scm.com/docs/git-format-patch#_base_tree_information]
> >
> > url:    https://github.com/intel-lab-lkp/linux/commits/Zheng-Wang/misc-hpilo-Fix-use-after-free-bug-in-ilo_remove-due-to-race-condition-with-ilo_open/20230418-005502
> > base:   char-misc/char-misc-testing
> > patch link:    https://lore.kernel.org/r/20230417165246.467723-1-zyytlz.wz%40163.com
> > patch subject: [PATCH] misc: hpilo: Fix use after free bug in ilo_remove due  to race condition with ilo_open
> > config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20230430/202304300909.ALHN6Vry-lkp@intel.com/config)
> > compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
> >
> > If you fix the issue, kindly add following tag where applicable
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Reported-by: Dan Carpenter <error27@gmail.com>
> > | Link: https://lore.kernel.org/r/202304300909.ALHN6Vry-lkp@intel.com/
> >
> > smatch warnings:
> > drivers/misc/hpilo.c:755 ilo_delete() warn: can 'ilo_hw' even be NULL?
> >
> > vim +/ilo_hw +755 drivers/misc/hpilo.c
> >
> > 13a22f45e6cb1e Zheng Wang      2023-04-18  749  static void ilo_delete(struct kref *kref)
> > 13a22f45e6cb1e Zheng Wang      2023-04-18  750  {
> > 13a22f45e6cb1e Zheng Wang      2023-04-18  751          int i, minor;
> > 13a22f45e6cb1e Zheng Wang      2023-04-18  752          struct ilo_hwinfo *ilo_hw = container_of(kref, struct ilo_hwinfo, refcnt);
> > 13a22f45e6cb1e Zheng Wang      2023-04-18  753          struct pci_dev *pdev = ilo_hw->ilo_dev;
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  754
> > ebf1b764aa5cb3 Mark Rusk       2012-11-06 @755          if (!ilo_hw)
> >                                                             ^^^^^^^
> >
> > ->refcnt member isn't the first struct member so this NULL check
> > doesn't make sense.  Generally checking container_of() is ugly.  Some
> > people do it and add BUILD_BUG_ON() to ensure that they're checking the
> > first struct member but really it's best to avoid that if possible.
> >
> > ebf1b764aa5cb3 Mark Rusk       2012-11-06  756                  return;
> > ebf1b764aa5cb3 Mark Rusk       2012-11-06  757
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  758          clear_device(ilo_hw);
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  759
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  760          minor = MINOR(ilo_hw->cdev.dev);
> > 98dcd59dd063dd Camuso, Tony    2012-06-10  761          for (i = minor; i < minor + max_ccb; i++)
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  762                  device_destroy(ilo_class, MKDEV(ilo_major, i));
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  763
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  764          cdev_del(&ilo_hw->cdev);
> > 9f7048412163d8 David Altobelli 2009-08-17  765          ilo_disable_interrupts(ilo_hw);
> > 9f7048412163d8 David Altobelli 2009-08-17  766          free_irq(pdev->irq, ilo_hw);
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  767          ilo_unmap_device(pdev, ilo_hw);
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  768          pci_release_regions(pdev);
> > bcdee04ea7ae04 Jiri Slaby      2012-09-13  769          /*
> > bcdee04ea7ae04 Jiri Slaby      2012-09-13  770           * pci_disable_device(pdev) used to be here. But this PCI device has
> > bcdee04ea7ae04 Jiri Slaby      2012-09-13  771           * two functions with interrupt lines connected to a single pin. The
> > bcdee04ea7ae04 Jiri Slaby      2012-09-13  772           * other one is a USB host controller. So when we disable the PIN here
> > bcdee04ea7ae04 Jiri Slaby      2012-09-13  773           * e.g. by rmmod hpilo, the controller stops working. It is because
> > bcdee04ea7ae04 Jiri Slaby      2012-09-13  774           * the interrupt link is disabled in ACPI since it is not refcounted
> > bcdee04ea7ae04 Jiri Slaby      2012-09-13  775           * yet. See acpi_pci_link_free_irq called from acpi_pci_irq_disable.
> > bcdee04ea7ae04 Jiri Slaby      2012-09-13  776           */
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  777          kfree(ilo_hw);
> > 98dcd59dd063dd Camuso, Tony    2012-06-10  778          ilo_hwdev[(minor / max_ccb)] = 0;
> > 89bcb05d9bbf8b David Altobelli 2008-07-02  779  }
> >
> > --
> > 0-DAY CI Kernel Test Service
> > https://github.com/intel/lkp-tests
> >
Zheng Hacker May 5, 2023, 7:35 a.m. UTC | #6 
Dan Carpenter <dan.carpenter@linaro.org> 于2023年5月5日周五 15:31写道：
>
> On Fri, May 05, 2023 at 12:01:17PM +0800, Zheng Hacker wrote:
> > Dear Dan,
> >
> > Thanks for your reply. I'm not so familiar with the code here. Is the
> > warning says we should check ilo_hw to see if it's not NULL?
> >
>
> Just delete the NULL check.  It's impossible.
>

Thanks for your explaination.

Best regards,
Zheng

> regards,
> dan carpenter
>
> > Best regards,
> > Zheng
> >
> > Dan Carpenter <dan.carpenter@linaro.org> 于2023年5月2日周二 19:46写道：
> > >
> > > Hi Zheng,
> > >
> > > kernel test robot noticed the following build warnings:
> > >
> > > https://git-scm.com/docs/git-format-patch#_base_tree_information]
> > >
> > > url:    https://github.com/intel-lab-lkp/linux/commits/Zheng-Wang/misc-hpilo-Fix-use-after-free-bug-in-ilo_remove-due-to-race-condition-with-ilo_open/20230418-005502
> > > base:   char-misc/char-misc-testing
> > > patch link:    https://lore.kernel.org/r/20230417165246.467723-1-zyytlz.wz%40163.com
> > > patch subject: [PATCH] misc: hpilo: Fix use after free bug in ilo_remove due  to race condition with ilo_open
> > > config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20230430/202304300909.ALHN6Vry-lkp@intel.com/config)
> > > compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
> > >
> > > If you fix the issue, kindly add following tag where applicable
> > > | Reported-by: kernel test robot <lkp@intel.com>
> > > | Reported-by: Dan Carpenter <error27@gmail.com>
> > > | Link: https://lore.kernel.org/r/202304300909.ALHN6Vry-lkp@intel.com/
> > >
> > > smatch warnings:
> > > drivers/misc/hpilo.c:755 ilo_delete() warn: can 'ilo_hw' even be NULL?
> > >
> > > vim +/ilo_hw +755 drivers/misc/hpilo.c
> > >
> > > 13a22f45e6cb1e Zheng Wang      2023-04-18  749  static void ilo_delete(struct kref *kref)
> > > 13a22f45e6cb1e Zheng Wang      2023-04-18  750  {
> > > 13a22f45e6cb1e Zheng Wang      2023-04-18  751          int i, minor;
> > > 13a22f45e6cb1e Zheng Wang      2023-04-18  752          struct ilo_hwinfo *ilo_hw = container_of(kref, struct ilo_hwinfo, refcnt);
> > > 13a22f45e6cb1e Zheng Wang      2023-04-18  753          struct pci_dev *pdev = ilo_hw->ilo_dev;
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  754
> > > ebf1b764aa5cb3 Mark Rusk       2012-11-06 @755          if (!ilo_hw)
> > >                                                             ^^^^^^^
> > >
> > > ->refcnt member isn't the first struct member so this NULL check
> > > doesn't make sense.  Generally checking container_of() is ugly.  Some
> > > people do it and add BUILD_BUG_ON() to ensure that they're checking the
> > > first struct member but really it's best to avoid that if possible.
> > >
> > > ebf1b764aa5cb3 Mark Rusk       2012-11-06  756                  return;
> > > ebf1b764aa5cb3 Mark Rusk       2012-11-06  757
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  758          clear_device(ilo_hw);
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  759
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  760          minor = MINOR(ilo_hw->cdev.dev);
> > > 98dcd59dd063dd Camuso, Tony    2012-06-10  761          for (i = minor; i < minor + max_ccb; i++)
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  762                  device_destroy(ilo_class, MKDEV(ilo_major, i));
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  763
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  764          cdev_del(&ilo_hw->cdev);
> > > 9f7048412163d8 David Altobelli 2009-08-17  765          ilo_disable_interrupts(ilo_hw);
> > > 9f7048412163d8 David Altobelli 2009-08-17  766          free_irq(pdev->irq, ilo_hw);
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  767          ilo_unmap_device(pdev, ilo_hw);
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  768          pci_release_regions(pdev);
> > > bcdee04ea7ae04 Jiri Slaby      2012-09-13  769          /*
> > > bcdee04ea7ae04 Jiri Slaby      2012-09-13  770           * pci_disable_device(pdev) used to be here. But this PCI device has
> > > bcdee04ea7ae04 Jiri Slaby      2012-09-13  771           * two functions with interrupt lines connected to a single pin. The
> > > bcdee04ea7ae04 Jiri Slaby      2012-09-13  772           * other one is a USB host controller. So when we disable the PIN here
> > > bcdee04ea7ae04 Jiri Slaby      2012-09-13  773           * e.g. by rmmod hpilo, the controller stops working. It is because
> > > bcdee04ea7ae04 Jiri Slaby      2012-09-13  774           * the interrupt link is disabled in ACPI since it is not refcounted
> > > bcdee04ea7ae04 Jiri Slaby      2012-09-13  775           * yet. See acpi_pci_link_free_irq called from acpi_pci_irq_disable.
> > > bcdee04ea7ae04 Jiri Slaby      2012-09-13  776           */
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  777          kfree(ilo_hw);
> > > 98dcd59dd063dd Camuso, Tony    2012-06-10  778          ilo_hwdev[(minor / max_ccb)] = 0;
> > > 89bcb05d9bbf8b David Altobelli 2008-07-02  779  }
> > >
> > > --
> > > 0-DAY CI Kernel Test Service
> > > https://github.com/intel/lkp-tests
> > >
diff mbox series

Patch

diff --git a/drivers/misc/hpilo.c b/drivers/misc/hpilo.c
index 8d00df9243c4..2e9af39e91a4 100644
--- a/drivers/misc/hpilo.c
+++ b/drivers/misc/hpilo.c
@@ -37,6 +37,8 @@  static const struct pci_device_id ilo_blacklist[] = {
 	{}
 };
 
+static void ilo_delete(struct kref *kref);
+
 static inline int get_entry_id(int entry)
 {
 	return (entry & ENTRY_MASK_DESCRIPTOR) >> ENTRY_BITPOS_DESCRIPTOR;
@@ -559,6 +561,7 @@  static int ilo_close(struct inode *ip, struct file *fp)
 		hw->ccb_alloc[slot]->ccb_cnt--;
 
 	spin_unlock(&hw->open_lock);
+	kref_put(&hw->refcnt, ilo_delete);
 
 	return 0;
 }
@@ -578,6 +581,7 @@  static int ilo_open(struct inode *ip, struct file *fp)
 	if (!data)
 		return -ENOMEM;
 
+	kref_get(&hw->refcnt);
 	spin_lock(&hw->open_lock);
 
 	/* each fd private_data holds sw/hw view of ccb */
@@ -633,6 +637,8 @@  static int ilo_open(struct inode *ip, struct file *fp)
 
 	if (!error)
 		fp->private_data = hw->ccb_alloc[slot];
+	else
+		kref_put(&hw->refcnt, ilo_delete);
 
 	return error;
 }
@@ -742,8 +748,15 @@  static int ilo_map_device(struct pci_dev *pdev, struct ilo_hwinfo *hw)
 
 static void ilo_remove(struct pci_dev *pdev)
 {
-	int i, minor;
 	struct ilo_hwinfo *ilo_hw = pci_get_drvdata(pdev);
+	kref_put(&ilo_hw->refcnt, ilo_delete);
+}
+
+static void ilo_delete(struct kref *kref)
+{
+	int i, minor;
+	struct ilo_hwinfo *ilo_hw = container_of(kref, struct ilo_hwinfo, refcnt);
+	struct pci_dev *pdev = ilo_hw->ilo_dev;
 
 	if (!ilo_hw)
 		return;
@@ -807,6 +820,7 @@  static int ilo_probe(struct pci_dev *pdev,
 		goto out;
 
 	ilo_hw->ilo_dev = pdev;
+	kref_init(&ilo_hw->refcnt);
 	spin_lock_init(&ilo_hw->alloc_lock);
 	spin_lock_init(&ilo_hw->fifo_lock);
 	spin_lock_init(&ilo_hw->open_lock);
diff --git a/drivers/misc/hpilo.h b/drivers/misc/hpilo.h
index d57c34680b09..ebc677eb45ae 100644
--- a/drivers/misc/hpilo.h
+++ b/drivers/misc/hpilo.h
@@ -62,6 +62,7 @@  struct ilo_hwinfo {
 	spinlock_t fifo_lock;
 
 	struct cdev cdev;
+	struct kref refcnt;
 };
 
 /* offset from mmio_vaddr for enabling doorbell interrupts */