2010-08-17 00:57:50

by Jin Dongming

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

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 <[email protected]>
---
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


2010-08-17 01:39:53

by Huang, Ying

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

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 <[email protected]>
> ---
> 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

2010-08-17 02:59:44

by Jin Dongming

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

(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 <[email protected]>
>> ---
>> 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
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
>

2010-08-17 04:18:23

by Huang, Ying

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

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

2010-08-17 09:18:19

by Jin Dongming

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

(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
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
>