[PATCH] misc/pvpanic: fix panic on accessing sysfs entries

[PATCH] misc/pvpanic: fix panic on accessing sysfs entries

[Mihai Carabas]

Commit 394febc9d0a6 ("misc/pvpanic: Make 'pvpanic_probe()' resource managed")
removed dev_set_drvdata from the probe function and accessing sysfs entries
from userspace is causing a panic in the kernel (pi = dev_get_drvdata(dev) ->
pi is NULL).

Mihai Carabas (1):
  misc/pvpanic: fix set driver data

 drivers/misc/pvpanic/pvpanic-mmio.c | 2 ++
 drivers/misc/pvpanic/pvpanic-pci.c  | 2 ++
 2 files changed, 4 insertions(+)

-- 
1.8.3.1

[PATCH] misc/pvpanic: fix set driver data

[Mihai Carabas]

Add again dev_set_drvdata in order for dev_get_drvdata to not return NULL.

Fixes: 394febc9d0a6 ("misc/pvpanic: Make 'pvpanic_probe()' resource managed")

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
---
 drivers/misc/pvpanic/pvpanic-mmio.c | 2 ++
 drivers/misc/pvpanic/pvpanic-pci.c  | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/misc/pvpanic/pvpanic-mmio.c b/drivers/misc/pvpanic/pvpanic-mmio.c
index be40160..874f94e 100644
--- a/drivers/misc/pvpanic/pvpanic-mmio.c
+++ b/drivers/misc/pvpanic/pvpanic-mmio.c
@@ -104,6 +104,8 @@ static int pvpanic_mmio_probe(struct platform_device *pdev)
 	pi->capability &= ioread8(base);
 	pi->events = pi->capability;
 
+	dev_set_drvdata(dev, pi);
+
 	return devm_pvpanic_probe(dev, pi);
 }
 
diff --git a/drivers/misc/pvpanic/pvpanic-pci.c b/drivers/misc/pvpanic/pvpanic-pci.c
index a43c401..2a26db8 100644
--- a/drivers/misc/pvpanic/pvpanic-pci.c
+++ b/drivers/misc/pvpanic/pvpanic-pci.c
@@ -96,6 +96,8 @@ static int pvpanic_pci_probe(struct pci_dev *pdev,
 	pi->capability &= ioread8(base);
 	pi->events = pi->capability;
 
+	dev_set_drvdata(dev, pi);
+
 	return devm_pvpanic_probe(&pdev->dev, pi);
 }
 
-- 
1.8.3.1

Re: [PATCH] misc/pvpanic: fix set driver data

[kernel test robot]

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Hi Mihai,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on char-misc/char-misc-testing]
[also build test ERROR on soc/for-next linus/master v5.14-rc6 next-20210818]
[cannot apply to linux/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Mihai-Carabas/misc-pvpanic-fix-set-driver-data/20210819-003204
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git 09cbd1df7d2615c19e40facbe31fdcb5f1ebfa96
config: riscv-randconfig-r042-20210816 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project d2b574a4dea5b718e4386bf2e26af0126e5978ce)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/0day-ci/linux/commit/d0d6a877210c6d9ac4505c8864294dbd975f31b1
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Mihai-Carabas/misc-pvpanic-fix-set-driver-data/20210819-003204
        git checkout d0d6a877210c6d9ac4505c8864294dbd975f31b1
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=riscv SHELL=/bin/bash drivers/misc/pvpanic/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/misc/pvpanic/pvpanic-pci.c:99:18: error: use of undeclared identifier 'dev'; did you mean 'pdev'?
           dev_set_drvdata(dev, pi);
                           ^~~
                           pdev
   drivers/misc/pvpanic/pvpanic-pci.c:73:46: note: 'pdev' declared here
   static int pvpanic_pci_probe(struct pci_dev *pdev,
                                                ^
   1 error generated.


vim +99 drivers/misc/pvpanic/pvpanic-pci.c

    72	
    73	static int pvpanic_pci_probe(struct pci_dev *pdev,
    74				     const struct pci_device_id *ent)
    75	{
    76		struct pvpanic_instance *pi;
    77		void __iomem *base;
    78		int ret;
    79	
    80		ret = pcim_enable_device(pdev);
    81		if (ret < 0)
    82			return ret;
    83	
    84		base = pcim_iomap(pdev, 0, 0);
    85		if (!base)
    86			return -ENOMEM;
    87	
    88		pi = devm_kmalloc(&pdev->dev, sizeof(*pi), GFP_KERNEL);
    89		if (!pi)
    90			return -ENOMEM;
    91	
    92		pi->base = base;
    93		pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
    94	
    95		/* initlize capability by RDPT */
    96		pi->capability &= ioread8(base);
    97		pi->events = pi->capability;
    98	
  > 99		dev_set_drvdata(dev, pi);
   100	
   101		return devm_pvpanic_probe(&pdev->dev, pi);
   102	}
   103	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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Re: [PATCH] misc/pvpanic: fix set driver data

[Andy Shevchenko]

On Wed, Aug 18, 2021 at 06:38:30PM +0300, Mihai Carabas wrote:

Thank you for the report and fix! My comments below.

> Add again dev_set_drvdata in order for dev_get_drvdata to not return NULL.

dev_set_drvdata()
dev_get_drvdata()

> Fixes: 394febc9d0a6 ("misc/pvpanic: Make 'pvpanic_probe()' resource managed")

> 

Shouldn't be blank line(s) in the tag block.

> Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>

...

> +	dev_set_drvdata(dev, pi);
> +
>  	return devm_pvpanic_probe(dev, pi);

I think it makes sense to have the above line as a part of pvpanic_probe().

-- 
With Best Regards,
Andy Shevchenko