linux-kernel - Re: [PATCH 4/4] [Patch-next] ACPI, APEI, HEST Fix the unsuitable usage of platform

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Date:	Tue, 17 Aug 2010 09:39:48 +0800
From:	Huang Ying <ying.huang@...el.com>
To:	Jin Dongming <jin.dongming@...css.fujitsu.com>
Cc:	Randy Dunlap <randy.dunlap@...cle.com>,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	Andi Kleen <andi@...stfloor.org>,
	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>,
	ACPI <linux-acpi@...r.kernel.org>,
	LKLM <linux-kernel@...r.kernel.org>
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 <jin.dongming@...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


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