[PATCH 4/4] [Patch-next] ACPI, APEI, HEST Fix the unsuitable usage of platform_data.

[PATCH 4/4] [Patch-next] ACPI, APEI, HEST Fix the unsuitable usage of platform_data.

[Jin Dongming]

platform_data in hest_parse_ghes() is used for saving the address of entry
information of erst_tab. When the device is failed to be added, platform_data
will be freed by platform_device_put(). But the value saved in platform_data
should not be freed here. If it is done, it will make system panic.

So I think platform_data should save the address of allocated memory
which saves entry information of erst_tab.

This patch fixed it and I confirmed it on x86_64 next-tree.

Signed-off-by: Jin Dongming <jin.dongming@np.css.fujitsu.com>
---
 drivers/acpi/apei/ghes.c |    2 +-
 drivers/acpi/apei/hest.c |   19 ++++++++++++++-----
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 385a605..b35c622 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -302,7 +302,7 @@ static int __devinit ghes_probe(struct platform_device *ghes_dev)
 	struct ghes *ghes = NULL;
 	int rc = -EINVAL;
 
-	generic = ghes_dev->dev.platform_data;
+	generic = *(struct acpi_hest_generic **)(ghes_dev->dev.platform_data);
 	if (!generic->enabled)
 		return -ENODEV;
 
diff --git a/drivers/acpi/apei/hest.c b/drivers/acpi/apei/hest.c
index 343168d..5a65e2a 100644
--- a/drivers/acpi/apei/hest.c
+++ b/drivers/acpi/apei/hest.c
@@ -137,20 +137,29 @@ static int hest_parse_ghes_count(struct acpi_hest_header *hest_hdr, void *data)
 
 static int hest_parse_ghes(struct acpi_hest_header *hest_hdr, void *data)
 {
-	struct acpi_hest_generic *generic;
+	void **platform_data;
 	struct platform_device *ghes_dev;
 	struct ghes_arr *ghes_arr = data;
 	int rc;
 
 	if (hest_hdr->type != ACPI_HEST_TYPE_GENERIC_ERROR)
 		return 0;
-	generic = (struct acpi_hest_generic *)hest_hdr;
-	if (!generic->enabled)
+
+	platform_data = kmalloc(sizeof(void *), GFP_KERNEL);
+	if (!platform_data)
+		return -ENOMEM;
+
+	*platform_data = hest_hdr;
+	if (!((struct acpi_hest_generic *)*platform_data)->enabled)
 		return 0;
+
 	ghes_dev = platform_device_alloc("GHES", hest_hdr->source_id);
-	if (!ghes_dev)
+	if (!ghes_dev) {
+		kfree(platform_data);
 		return -ENOMEM;
-	ghes_dev->dev.platform_data = generic;
+	}
+
+	ghes_dev->dev.platform_data = platform_data;
 	rc = platform_device_add(ghes_dev);
 	if (rc)
 		goto err;
-- 
1.7.1.1

Re: [PATCH 4/4] [Patch-next] ACPI, APEI, HEST Fix the unsuitable usage of platform_data.

[Huang Ying]

On Tue, 2010-08-17 at 08:58 +0800, Jin Dongming wrote:
> platform_data in hest_parse_ghes() is used for saving the address of entry
> information of erst_tab. When the device is failed to be added, platform_data
> will be freed by platform_device_put(). But the value saved in platform_data
> should not be freed here. If it is done, it will make system panic.

Good catch. Thanks.

> So I think platform_data should save the address of allocated memory
> which saves entry information of erst_tab.
> 
> This patch fixed it and I confirmed it on x86_64 next-tree.
> 
> Signed-off-by: Jin Dongming <jin.dongming@np.css.fujitsu.com>
> ---
>  drivers/acpi/apei/ghes.c |    2 +-
>  drivers/acpi/apei/hest.c |   19 ++++++++++++++-----
>  2 files changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 385a605..b35c622 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -302,7 +302,7 @@ static int __devinit ghes_probe(struct platform_device *ghes_dev)
>  	struct ghes *ghes = NULL;
>  	int rc = -EINVAL;
>  
> -	generic = ghes_dev->dev.platform_data;
> +	generic = *(struct acpi_hest_generic **)(ghes_dev->dev.platform_data);
>  	if (!generic->enabled)
>  		return -ENODEV;
>  
> diff --git a/drivers/acpi/apei/hest.c b/drivers/acpi/apei/hest.c
> index 343168d..5a65e2a 100644
> --- a/drivers/acpi/apei/hest.c
> +++ b/drivers/acpi/apei/hest.c
> @@ -137,20 +137,29 @@ static int hest_parse_ghes_count(struct acpi_hest_header *hest_hdr, void *data)
>  
>  static int hest_parse_ghes(struct acpi_hest_header *hest_hdr, void *data)
>  {
> -	struct acpi_hest_generic *generic;
> +	void **platform_data;
>  	struct platform_device *ghes_dev;
>  	struct ghes_arr *ghes_arr = data;
>  	int rc;
>  
>  	if (hest_hdr->type != ACPI_HEST_TYPE_GENERIC_ERROR)
>  		return 0;
> -	generic = (struct acpi_hest_generic *)hest_hdr;
> -	if (!generic->enabled)
> +
> +	platform_data = kmalloc(sizeof(void *), GFP_KERNEL);
> +	if (!platform_data)
> +		return -ENOMEM;
> +
> +	*platform_data = hest_hdr;
> +	if (!((struct acpi_hest_generic *)*platform_data)->enabled)
>  		return 0;
> +
>  	ghes_dev = platform_device_alloc("GHES", hest_hdr->source_id);
> -	if (!ghes_dev)
> +	if (!ghes_dev) {
> +		kfree(platform_data);
>  		return -ENOMEM;
> -	ghes_dev->dev.platform_data = generic;
> +	}
> +
> +	ghes_dev->dev.platform_data = platform_data;
>  	rc = platform_device_add(ghes_dev);
>  	if (rc)
>  		goto err;

Why not use platform_device_add_data?

Best Regards,
Huang Ying

Re: [PATCH 4/4] [Patch-next] ACPI, APEI, HEST Fix the unsuitable usage of platform_data.

[Jin Dongming]

(2010/08/17 10:39), Huang Ying wrote:
> On Tue, 2010-08-17 at 08:58 +0800, Jin Dongming wrote:
>> platform_data in hest_parse_ghes() is used for saving the address of entry
>> information of erst_tab. When the device is failed to be added, platform_data
>> will be freed by platform_device_put(). But the value saved in platform_data
>> should not be freed here. If it is done, it will make system panic.
> 
> Good catch. Thanks.
> 
>> So I think platform_data should save the address of allocated memory
>> which saves entry information of erst_tab.
>>
>> This patch fixed it and I confirmed it on x86_64 next-tree.
>>
>> Signed-off-by: Jin Dongming <jin.dongming@np.css.fujitsu.com>
>> ---
>>  drivers/acpi/apei/ghes.c |    2 +-
>>  drivers/acpi/apei/hest.c |   19 ++++++++++++++-----
>>  2 files changed, 15 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
>> index 385a605..b35c622 100644
>> --- a/drivers/acpi/apei/ghes.c
>> +++ b/drivers/acpi/apei/ghes.c
>> @@ -302,7 +302,7 @@ static int __devinit ghes_probe(struct platform_device *ghes_dev)
>>  	struct ghes *ghes = NULL;
>>  	int rc = -EINVAL;
>>  
>> -	generic = ghes_dev->dev.platform_data;
>> +	generic = *(struct acpi_hest_generic **)(ghes_dev->dev.platform_data);
>>  	if (!generic->enabled)
>>  		return -ENODEV;
>>  
>> diff --git a/drivers/acpi/apei/hest.c b/drivers/acpi/apei/hest.c
>> index 343168d..5a65e2a 100644
>> --- a/drivers/acpi/apei/hest.c
>> +++ b/drivers/acpi/apei/hest.c
>> @@ -137,20 +137,29 @@ static int hest_parse_ghes_count(struct acpi_hest_header *hest_hdr, void *data)
>>  
>>  static int hest_parse_ghes(struct acpi_hest_header *hest_hdr, void *data)
>>  {
>> -	struct acpi_hest_generic *generic;
>> +	void **platform_data;
>>  	struct platform_device *ghes_dev;
>>  	struct ghes_arr *ghes_arr = data;
>>  	int rc;
>>  
>>  	if (hest_hdr->type != ACPI_HEST_TYPE_GENERIC_ERROR)
>>  		return 0;
>> -	generic = (struct acpi_hest_generic *)hest_hdr;
>> -	if (!generic->enabled)
>> +
>> +	platform_data = kmalloc(sizeof(void *), GFP_KERNEL);
>> +	if (!platform_data)
>> +		return -ENOMEM;
>> +
>> +	*platform_data = hest_hdr;
>> +	if (!((struct acpi_hest_generic *)*platform_data)->enabled)
>>  		return 0;
>> +
>>  	ghes_dev = platform_device_alloc("GHES", hest_hdr->source_id);
>> -	if (!ghes_dev)
>> +	if (!ghes_dev) {
>> +		kfree(platform_data);
>>  		return -ENOMEM;
>> -	ghes_dev->dev.platform_data = generic;
>> +	}
>> +
>> +	ghes_dev->dev.platform_data = platform_data;
>>  	rc = platform_device_add(ghes_dev);
>>  	if (rc)
>>  		goto err;
> 
> Why not use platform_device_add_data?
Here what should be done is to transport the pointer of hest_hdr to platform_data,
so I think that it could be done successfully by allocating 8byte of memory.
If the platform_device_add_data() is used, the more memory will be allocated. 

So I think this method is better than using platform_device_add_data().

> 
> Best Regards,
> Huang Ying
> 
> 
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Re: [PATCH 4/4] [Patch-next] ACPI, APEI, HEST Fix the unsuitable usage of platform_data.

[Huang Ying]

On Tue, 2010-08-17 at 11:00 +0800, Jin Dongming wrote:
> > Why not use platform_device_add_data?
> Here what should be done is to transport the pointer of hest_hdr to platform_data,
> so I think that it could be done successfully by allocating 8byte of memory.
> If the platform_device_add_data() is used, the more memory will be allocated. 
> 
> So I think this method is better than using platform_device_add_data().

You can specify allocation size for platform_device_add_data(), so no
more memory will be allocated.

Best Regards,
Huang Ying

Re: [PATCH 4/4] [Patch-next] ACPI, APEI, HEST Fix the unsuitable usage of platform_data.

[Jin Dongming]

(2010/08/17 13:18), Huang Ying wrote:
> On Tue, 2010-08-17 at 11:00 +0800, Jin Dongming wrote:
>>> Why not use platform_device_add_data?
>> Here what should be done is to transport the pointer of hest_hdr to platform_data,
>> so I think that it could be done successfully by allocating 8byte of memory.
>> If the platform_device_add_data() is used, the more memory will be allocated. 
>>
>> So I think this method is better than using platform_device_add_data().
> 
> You can specify allocation size for platform_device_add_data(), so no
> more memory will be allocated.
> 
> Best Regards,
> Huang Ying

I am sorry for replying late.
I will modify my patch and resend it again.

Best Regards,
Jin Dongming
> 
> 
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> 
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