[v4] mmc: block: Fix bug when removing RPMB chardev

Message ID 20171004091007.26729-1-linus.walleij@linaro.org
State New
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Series
  • [v4] mmc: block: Fix bug when removing RPMB chardev
Related show

Commit Message

Linus Walleij Oct. 4, 2017, 9:10 a.m.
I forgot to account for the fact that the device core holds a
reference to a device added with device_initialize() that need
to be released with a corresponding put_device() to reach a 0
refcount at the end of the lifecycle.

This led to a NULL pointer reference when freeing the device
when e.g. unbidning the host device in sysfs.

Fix this and use the device .release() callback to free the
IDA and free:ing the memory used by the RPMB device.

Before this patch:

/sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind
[   29.797332] mmc3: card 0001 removed
[   29.810791] Unable to handle kernel NULL pointer dereference at
               virtual address 00000050
[   29.818878] pgd = de70c000
[   29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000
[   29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM
[   29.833282] Modules linked in:
[   29.836334] CPU: 1 PID: 154 Comm: sh Not tainted
               4.14.0-rc3-00039-g83318e309566-dirty #736
[   29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support)
[   29.851562] task: de572700 task.stack: de742000
[   29.856079] PC is at kernfs_find_ns+0x8/0x100
[   29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48

After this patch:

/sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind
[   20.623382] mmc3: card 0001 removed

Fixes: 0ab0c7c0e65a ("mmc: block: Convert RPMB to a character device")
Reported-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

---
ChangeLog v3->v4:
- Also skip the lock now that we take it inside mmc_blk_get()/
  mmc_blk_put()
ChangeLog v2->v3:
- Fix the block device reference counting: instead of manipulating
  md->usage directly, call the proper refcounting functions
  mmc_blk_get() and mmc_blk_put().
ChangeLog v1->v2:
- Drop the print from removing the RPMB partition
- Refactor the error path of the RPMB to use refcounting
- Drop the verbose comment on refcounts
---
 drivers/mmc/core/block.c | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

-- 
2.13.5

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Comments

Ulf Hansson Oct. 4, 2017, 9:39 a.m. | #1
On 4 October 2017 at 11:10, Linus Walleij <linus.walleij@linaro.org> wrote:
> I forgot to account for the fact that the device core holds a

> reference to a device added with device_initialize() that need

> to be released with a corresponding put_device() to reach a 0

> refcount at the end of the lifecycle.

>

> This led to a NULL pointer reference when freeing the device

> when e.g. unbidning the host device in sysfs.

>

> Fix this and use the device .release() callback to free the

> IDA and free:ing the memory used by the RPMB device.

>

> Before this patch:

>

> /sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind

> [   29.797332] mmc3: card 0001 removed

> [   29.810791] Unable to handle kernel NULL pointer dereference at

>                virtual address 00000050

> [   29.818878] pgd = de70c000

> [   29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000

> [   29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM

> [   29.833282] Modules linked in:

> [   29.836334] CPU: 1 PID: 154 Comm: sh Not tainted

>                4.14.0-rc3-00039-g83318e309566-dirty #736

> [   29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support)

> [   29.851562] task: de572700 task.stack: de742000

> [   29.856079] PC is at kernfs_find_ns+0x8/0x100

> [   29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48

>

> After this patch:

>

> /sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind

> [   20.623382] mmc3: card 0001 removed

>

> Fixes: 0ab0c7c0e65a ("mmc: block: Convert RPMB to a character device")

> Reported-by: Adrian Hunter <adrian.hunter@intel.com>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>


This looks good to me. However I wait a bit to get an ack from Adrian
as well - before I queue this up for fixes!

Kind regards
Uffe

> ---

> ChangeLog v3->v4:

> - Also skip the lock now that we take it inside mmc_blk_get()/

>   mmc_blk_put()

> ChangeLog v2->v3:

> - Fix the block device reference counting: instead of manipulating

>   md->usage directly, call the proper refcounting functions

>   mmc_blk_get() and mmc_blk_put().

> ChangeLog v1->v2:

> - Drop the print from removing the RPMB partition

> - Refactor the error path of the RPMB to use refcounting

> - Drop the verbose comment on refcounts

> ---

>  drivers/mmc/core/block.c | 32 ++++++++++++++++++--------------

>  1 file changed, 18 insertions(+), 14 deletions(-)

>

> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c

> index c29dbcec7c61..ea80ff4cd7f9 100644

> --- a/drivers/mmc/core/block.c

> +++ b/drivers/mmc/core/block.c

> @@ -2298,9 +2298,7 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp)

>

>         get_device(&rpmb->dev);

>         filp->private_data = rpmb;

> -       mutex_lock(&open_lock);

> -       rpmb->md->usage++;

> -       mutex_unlock(&open_lock);

> +       mmc_blk_get(rpmb->md->disk);

>

>         return nonseekable_open(inode, filp);

>  }

> @@ -2311,9 +2309,7 @@ static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp)

>                                                   struct mmc_rpmb_data, chrdev);

>

>         put_device(&rpmb->dev);

> -       mutex_lock(&open_lock);

> -       rpmb->md->usage--;

> -       mutex_unlock(&open_lock);

> +       mmc_blk_put(rpmb->md);

>

>         return 0;

>  }

> @@ -2329,6 +2325,13 @@ static const struct file_operations mmc_rpmb_fileops = {

>  #endif

>  };

>

> +static void mmc_blk_rpmb_device_release(struct device *dev)

> +{

> +       struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);

> +

> +       ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> +       kfree(rpmb);

> +}

>

>  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>                                    struct mmc_blk_data *md,

> @@ -2347,8 +2350,10 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>                 return devidx;

>

>         rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL);

> -       if (!rpmb)

> +       if (!rpmb) {

> +               ida_simple_remove(&mmc_rpmb_ida, devidx);

>                 return -ENOMEM;

> +       }

>

>         snprintf(rpmb_name, sizeof(rpmb_name),

>                  "mmcblk%u%s", card->host->index, subname ? subname : "");

> @@ -2359,6 +2364,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>         rpmb->dev.bus = &mmc_rpmb_bus_type;

>         rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id);

>         rpmb->dev.parent = &card->dev;

> +       rpmb->dev.release = mmc_blk_rpmb_device_release;

>         device_initialize(&rpmb->dev);

>         dev_set_drvdata(&rpmb->dev, rpmb);

>         rpmb->md = md;

> @@ -2368,7 +2374,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>         ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev);

>         if (ret) {

>                 pr_err("%s: could not add character device\n", rpmb_name);

> -               goto out_remove_ida;

> +               goto out_put_device;

>         }

>

>         list_add(&rpmb->node, &md->rpmbs);

> @@ -2383,18 +2389,16 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>

>         return 0;

>

> -out_remove_ida:

> -       ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> -       kfree(rpmb);

> +out_put_device:

> +       put_device(&rpmb->dev);

>         return ret;

>  }

>

>  static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)

> +

>  {

>         cdev_device_del(&rpmb->chrdev, &rpmb->dev);

> -       device_del(&rpmb->dev);

> -       ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> -       kfree(rpmb);

> +       put_device(&rpmb->dev);

>  }

>

>  /* MMC Physical partitions consist of two boot partitions and

> --

> 2.13.5

>

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Adrian Hunter Oct. 4, 2017, 12:27 p.m. | #2
On 04/10/17 12:10, Linus Walleij wrote:
> I forgot to account for the fact that the device core holds a

> reference to a device added with device_initialize() that need

> to be released with a corresponding put_device() to reach a 0

> refcount at the end of the lifecycle.

> 

> This led to a NULL pointer reference when freeing the device

> when e.g. unbidning the host device in sysfs.

> 

> Fix this and use the device .release() callback to free the

> IDA and free:ing the memory used by the RPMB device.

> 

> Before this patch:

> 

> /sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind

> [   29.797332] mmc3: card 0001 removed

> [   29.810791] Unable to handle kernel NULL pointer dereference at

>                virtual address 00000050

> [   29.818878] pgd = de70c000

> [   29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000

> [   29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM

> [   29.833282] Modules linked in:

> [   29.836334] CPU: 1 PID: 154 Comm: sh Not tainted

>                4.14.0-rc3-00039-g83318e309566-dirty #736

> [   29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support)

> [   29.851562] task: de572700 task.stack: de742000

> [   29.856079] PC is at kernfs_find_ns+0x8/0x100

> [   29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48

> 

> After this patch:

> 

> /sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind

> [   20.623382] mmc3: card 0001 removed

> 

> Fixes: 0ab0c7c0e65a ("mmc: block: Convert RPMB to a character device")

> Reported-by: Adrian Hunter <adrian.hunter@intel.com>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>



Acked-by: Adrian Hunter <adrian.hunter@intel.com>



> ---

> ChangeLog v3->v4:

> - Also skip the lock now that we take it inside mmc_blk_get()/

>   mmc_blk_put()

> ChangeLog v2->v3:

> - Fix the block device reference counting: instead of manipulating

>   md->usage directly, call the proper refcounting functions

>   mmc_blk_get() and mmc_blk_put().

> ChangeLog v1->v2:

> - Drop the print from removing the RPMB partition

> - Refactor the error path of the RPMB to use refcounting

> - Drop the verbose comment on refcounts

> ---

>  drivers/mmc/core/block.c | 32 ++++++++++++++++++--------------

>  1 file changed, 18 insertions(+), 14 deletions(-)

> 

> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c

> index c29dbcec7c61..ea80ff4cd7f9 100644

> --- a/drivers/mmc/core/block.c

> +++ b/drivers/mmc/core/block.c

> @@ -2298,9 +2298,7 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp)

>  

>  	get_device(&rpmb->dev);

>  	filp->private_data = rpmb;

> -	mutex_lock(&open_lock);

> -	rpmb->md->usage++;

> -	mutex_unlock(&open_lock);

> +	mmc_blk_get(rpmb->md->disk);

>  

>  	return nonseekable_open(inode, filp);

>  }

> @@ -2311,9 +2309,7 @@ static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp)

>  						  struct mmc_rpmb_data, chrdev);

>  

>  	put_device(&rpmb->dev);

> -	mutex_lock(&open_lock);

> -	rpmb->md->usage--;

> -	mutex_unlock(&open_lock);

> +	mmc_blk_put(rpmb->md);

>  

>  	return 0;

>  }

> @@ -2329,6 +2325,13 @@ static const struct file_operations mmc_rpmb_fileops = {

>  #endif

>  };

>  

> +static void mmc_blk_rpmb_device_release(struct device *dev)

> +{

> +	struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);

> +

> +	ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> +	kfree(rpmb);

> +}

>  

>  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>  				   struct mmc_blk_data *md,

> @@ -2347,8 +2350,10 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>  		return devidx;

>  

>  	rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL);

> -	if (!rpmb)

> +	if (!rpmb) {

> +		ida_simple_remove(&mmc_rpmb_ida, devidx);

>  		return -ENOMEM;

> +	}

>  

>  	snprintf(rpmb_name, sizeof(rpmb_name),

>  		 "mmcblk%u%s", card->host->index, subname ? subname : "");

> @@ -2359,6 +2364,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>  	rpmb->dev.bus = &mmc_rpmb_bus_type;

>  	rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id);

>  	rpmb->dev.parent = &card->dev;

> +	rpmb->dev.release = mmc_blk_rpmb_device_release;

>  	device_initialize(&rpmb->dev);

>  	dev_set_drvdata(&rpmb->dev, rpmb);

>  	rpmb->md = md;

> @@ -2368,7 +2374,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>  	ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev);

>  	if (ret) {

>  		pr_err("%s: could not add character device\n", rpmb_name);

> -		goto out_remove_ida;

> +		goto out_put_device;

>  	}

>  

>  	list_add(&rpmb->node, &md->rpmbs);

> @@ -2383,18 +2389,16 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>  

>  	return 0;

>  

> -out_remove_ida:

> -	ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> -	kfree(rpmb);

> +out_put_device:

> +	put_device(&rpmb->dev);

>  	return ret;

>  }

>  

>  static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)

> +

>  {

>  	cdev_device_del(&rpmb->chrdev, &rpmb->dev);

> -	device_del(&rpmb->dev);

> -	ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> -	kfree(rpmb);

> +	put_device(&rpmb->dev);

>  }

>  

>  /* MMC Physical partitions consist of two boot partitions and

> 


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Ulf Hansson Oct. 4, 2017, 12:57 p.m. | #3
On 4 October 2017 at 11:10, Linus Walleij <linus.walleij@linaro.org> wrote:
> I forgot to account for the fact that the device core holds a

> reference to a device added with device_initialize() that need

> to be released with a corresponding put_device() to reach a 0

> refcount at the end of the lifecycle.

>

> This led to a NULL pointer reference when freeing the device

> when e.g. unbidning the host device in sysfs.

>

> Fix this and use the device .release() callback to free the

> IDA and free:ing the memory used by the RPMB device.

>

> Before this patch:

>

> /sys/bus/amba/drivers/mmci-pl18x$ echo 80114000.sdi4_per2 > unbind

> [   29.797332] mmc3: card 0001 removed

> [   29.810791] Unable to handle kernel NULL pointer dereference at

>                virtual address 00000050

> [   29.818878] pgd = de70c000

> [   29.821624] [00000050] *pgd=1e70a831, *pte=00000000, *ppte=00000000

> [   29.827911] Internal error: Oops: 17 [#1] PREEMPT SMP ARM

> [   29.833282] Modules linked in:

> [   29.836334] CPU: 1 PID: 154 Comm: sh Not tainted

>                4.14.0-rc3-00039-g83318e309566-dirty #736

> [   29.844604] Hardware name: ST-Ericsson Ux5x0 platform (Device Tree Support)

> [   29.851562] task: de572700 task.stack: de742000

> [   29.856079] PC is at kernfs_find_ns+0x8/0x100

> [   29.860443] LR is at kernfs_find_and_get_ns+0x30/0x48

>

> After this patch:

>

> /sys/bus/amba/drivers/mmci-pl18x$ echo 80005000.sdi4_per2 > unbind

> [   20.623382] mmc3: card 0001 removed

>

> Fixes: 0ab0c7c0e65a ("mmc: block: Convert RPMB to a character device")

> Reported-by: Adrian Hunter <adrian.hunter@intel.com>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>


Thanks, applied for next!

Kind regards
Uffe

> ---

> ChangeLog v3->v4:

> - Also skip the lock now that we take it inside mmc_blk_get()/

>   mmc_blk_put()

> ChangeLog v2->v3:

> - Fix the block device reference counting: instead of manipulating

>   md->usage directly, call the proper refcounting functions

>   mmc_blk_get() and mmc_blk_put().

> ChangeLog v1->v2:

> - Drop the print from removing the RPMB partition

> - Refactor the error path of the RPMB to use refcounting

> - Drop the verbose comment on refcounts

> ---

>  drivers/mmc/core/block.c | 32 ++++++++++++++++++--------------

>  1 file changed, 18 insertions(+), 14 deletions(-)

>

> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c

> index c29dbcec7c61..ea80ff4cd7f9 100644

> --- a/drivers/mmc/core/block.c

> +++ b/drivers/mmc/core/block.c

> @@ -2298,9 +2298,7 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp)

>

>         get_device(&rpmb->dev);

>         filp->private_data = rpmb;

> -       mutex_lock(&open_lock);

> -       rpmb->md->usage++;

> -       mutex_unlock(&open_lock);

> +       mmc_blk_get(rpmb->md->disk);

>

>         return nonseekable_open(inode, filp);

>  }

> @@ -2311,9 +2309,7 @@ static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp)

>                                                   struct mmc_rpmb_data, chrdev);

>

>         put_device(&rpmb->dev);

> -       mutex_lock(&open_lock);

> -       rpmb->md->usage--;

> -       mutex_unlock(&open_lock);

> +       mmc_blk_put(rpmb->md);

>

>         return 0;

>  }

> @@ -2329,6 +2325,13 @@ static const struct file_operations mmc_rpmb_fileops = {

>  #endif

>  };

>

> +static void mmc_blk_rpmb_device_release(struct device *dev)

> +{

> +       struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);

> +

> +       ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> +       kfree(rpmb);

> +}

>

>  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>                                    struct mmc_blk_data *md,

> @@ -2347,8 +2350,10 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>                 return devidx;

>

>         rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL);

> -       if (!rpmb)

> +       if (!rpmb) {

> +               ida_simple_remove(&mmc_rpmb_ida, devidx);

>                 return -ENOMEM;

> +       }

>

>         snprintf(rpmb_name, sizeof(rpmb_name),

>                  "mmcblk%u%s", card->host->index, subname ? subname : "");

> @@ -2359,6 +2364,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>         rpmb->dev.bus = &mmc_rpmb_bus_type;

>         rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id);

>         rpmb->dev.parent = &card->dev;

> +       rpmb->dev.release = mmc_blk_rpmb_device_release;

>         device_initialize(&rpmb->dev);

>         dev_set_drvdata(&rpmb->dev, rpmb);

>         rpmb->md = md;

> @@ -2368,7 +2374,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>         ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev);

>         if (ret) {

>                 pr_err("%s: could not add character device\n", rpmb_name);

> -               goto out_remove_ida;

> +               goto out_put_device;

>         }

>

>         list_add(&rpmb->node, &md->rpmbs);

> @@ -2383,18 +2389,16 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,

>

>         return 0;

>

> -out_remove_ida:

> -       ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> -       kfree(rpmb);

> +out_put_device:

> +       put_device(&rpmb->dev);

>         return ret;

>  }

>

>  static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)

> +

>  {

>         cdev_device_del(&rpmb->chrdev, &rpmb->dev);

> -       device_del(&rpmb->dev);

> -       ida_simple_remove(&mmc_rpmb_ida, rpmb->id);

> -       kfree(rpmb);

> +       put_device(&rpmb->dev);

>  }

>

>  /* MMC Physical partitions consist of two boot partitions and

> --

> 2.13.5

>

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Patch

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index c29dbcec7c61..ea80ff4cd7f9 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2298,9 +2298,7 @@  static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp)
 
 	get_device(&rpmb->dev);
 	filp->private_data = rpmb;
-	mutex_lock(&open_lock);
-	rpmb->md->usage++;
-	mutex_unlock(&open_lock);
+	mmc_blk_get(rpmb->md->disk);
 
 	return nonseekable_open(inode, filp);
 }
@@ -2311,9 +2309,7 @@  static int mmc_rpmb_chrdev_release(struct inode *inode, struct file *filp)
 						  struct mmc_rpmb_data, chrdev);
 
 	put_device(&rpmb->dev);
-	mutex_lock(&open_lock);
-	rpmb->md->usage--;
-	mutex_unlock(&open_lock);
+	mmc_blk_put(rpmb->md);
 
 	return 0;
 }
@@ -2329,6 +2325,13 @@  static const struct file_operations mmc_rpmb_fileops = {
 #endif
 };
 
+static void mmc_blk_rpmb_device_release(struct device *dev)
+{
+	struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
+
+	ida_simple_remove(&mmc_rpmb_ida, rpmb->id);
+	kfree(rpmb);
+}
 
 static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
 				   struct mmc_blk_data *md,
@@ -2347,8 +2350,10 @@  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
 		return devidx;
 
 	rpmb = kzalloc(sizeof(*rpmb), GFP_KERNEL);
-	if (!rpmb)
+	if (!rpmb) {
+		ida_simple_remove(&mmc_rpmb_ida, devidx);
 		return -ENOMEM;
+	}
 
 	snprintf(rpmb_name, sizeof(rpmb_name),
 		 "mmcblk%u%s", card->host->index, subname ? subname : "");
@@ -2359,6 +2364,7 @@  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
 	rpmb->dev.bus = &mmc_rpmb_bus_type;
 	rpmb->dev.devt = MKDEV(MAJOR(mmc_rpmb_devt), rpmb->id);
 	rpmb->dev.parent = &card->dev;
+	rpmb->dev.release = mmc_blk_rpmb_device_release;
 	device_initialize(&rpmb->dev);
 	dev_set_drvdata(&rpmb->dev, rpmb);
 	rpmb->md = md;
@@ -2368,7 +2374,7 @@  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
 	ret = cdev_device_add(&rpmb->chrdev, &rpmb->dev);
 	if (ret) {
 		pr_err("%s: could not add character device\n", rpmb_name);
-		goto out_remove_ida;
+		goto out_put_device;
 	}
 
 	list_add(&rpmb->node, &md->rpmbs);
@@ -2383,18 +2389,16 @@  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
 
 	return 0;
 
-out_remove_ida:
-	ida_simple_remove(&mmc_rpmb_ida, rpmb->id);
-	kfree(rpmb);
+out_put_device:
+	put_device(&rpmb->dev);
 	return ret;
 }
 
 static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)
+
 {
 	cdev_device_del(&rpmb->chrdev, &rpmb->dev);
-	device_del(&rpmb->dev);
-	ida_simple_remove(&mmc_rpmb_ida, rpmb->id);
-	kfree(rpmb);
+	put_device(&rpmb->dev);
 }
 
 /* MMC Physical partitions consist of two boot partitions and