2020-03-03 14:11:13

by John Allen

Subject: [PATCH 1/2] crypto/ccp: Cleanup misc_dev on sev_exit()

Explicitly free and clear misc_dev in sev_exit(). Since devm_kzalloc()
associates misc_dev with the first device that gets probed, change from
devm_kzalloc() to kzalloc() and explicitly free memory in sev_exit() as
the first device probed is not guaranteed to be the last device released.
To ensure that the variable gets properly set to NULL, remove the local
definition of misc_dev.

Fixes: 200664d5237f ("crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support")
Signed-off-by: John Allen <[email protected]>
---
drivers/crypto/ccp/sev-dev.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index e467860f797d..aa591dae067c 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -896,9 +896,9 @@ EXPORT_SYMBOL_GPL(sev_guest_df_flush);

static void sev_exit(struct kref *ref)
{
- struct sev_misc_dev *misc_dev = container_of(ref, struct sev_misc_dev, refcount);
-
misc_deregister(&misc_dev->misc);
+ kfree(misc_dev);
+ misc_dev = NULL;
}

static int sev_misc_init(struct sev_device *sev)
@@ -916,7 +916,7 @@ static int sev_misc_init(struct sev_device *sev)
if (!misc_dev) {
struct miscdevice *misc;

- misc_dev = devm_kzalloc(dev, sizeof(*misc_dev), GFP_KERNEL);
+ misc_dev = kzalloc(sizeof(*misc_dev), GFP_KERNEL);
if (!misc_dev)
return -ENOMEM;

--
2.18.2

2020-03-06 15:56:41

by Tom Lendacky

Subject: Re: [PATCH 1/2] crypto/ccp: Cleanup misc_dev on sev_exit()

On 3/3/20 7:57 AM, John Allen wrote:
> Explicitly free and clear misc_dev in sev_exit(). Since devm_kzalloc()
> associates misc_dev with the first device that gets probed, change from
> devm_kzalloc() to kzalloc() and explicitly free memory in sev_exit() as
> the first device probed is not guaranteed to be the last device released.
> To ensure that the variable gets properly set to NULL, remove the local
> definition of misc_dev.
>
> Fixes: 200664d5237f ("crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support")
> Signed-off-by: John Allen <[email protected]>

Acked-by: Tom Lendacky <[email protected]>

> ---
> drivers/crypto/ccp/sev-dev.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index e467860f797d..aa591dae067c 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -896,9 +896,9 @@ EXPORT_SYMBOL_GPL(sev_guest_df_flush);
>
> static void sev_exit(struct kref *ref)
> {
> - struct sev_misc_dev *misc_dev = container_of(ref, struct sev_misc_dev, refcount);
> -
> misc_deregister(&misc_dev->misc);
> + kfree(misc_dev);
> + misc_dev = NULL;
> }
>
> static int sev_misc_init(struct sev_device *sev)
> @@ -916,7 +916,7 @@ static int sev_misc_init(struct sev_device *sev)
> if (!misc_dev) {
> struct miscdevice *misc;
>
> - misc_dev = devm_kzalloc(dev, sizeof(*misc_dev), GFP_KERNEL);
> + misc_dev = kzalloc(sizeof(*misc_dev), GFP_KERNEL);
> if (!misc_dev)
> return -ENOMEM;
>
>