Re: [PATCH v2] acer-wmi: fix memory leaks in wmab_execute error path

[Axel Lin]

hi Andrew,
I just found acer-wmi-fix-memory-leaks-in-wmab_execute-error-path.patch added 
to -mm tree.
But I think the V2 version is the correct one.
If the second wmab_execute fail (for any reason) , we need to free the existing 
buffer before return status.
Sould I resend the patch?


Regards,
Axel

於 五，2010-07-09 於 12:37 +0800，Axel Lin 提到：
> When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
> the caller must kfree the returned buffer if AE_OK is returned.
> 
> Call Trace:
> wmab_execute
>   -> wmi_evaluate_method
>     -> acpi_evaluate_object
> 
> Thus if callers of wmab_execute() pass ACPI_ALLOCATE_BUFFER,
> the return buffer must be kfreed if wmab_execute return AE_OK.
> 
> Signed-off-by: Axel Lin <axel....@gmail.com>
> ---
>  drivers/platform/x86/acer-wmi.c |   11 ++++++++++-
>  1 files changed, 10 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
> index 1ea6c43..3f44446 100644
> --- a/drivers/platform/x86/acer-wmi.c
> +++ b/drivers/platform/x86/acer-wmi.c
> @@ -555,6 +555,7 @@ static acpi_status AMW0_find_mailled(void)
>       obj->buffer.length == sizeof(struct wmab_ret)) {
>               ret = *((struct wmab_ret *) obj->buffer.pointer);
>       } else {
> +             kfree(out.pointer);
>               return AE_ERROR;
>       }
>  
> @@ -598,6 +599,7 @@ static acpi_status AMW0_set_capabilities(void)
>       obj->buffer.length == sizeof(struct wmab_ret)) {
>               ret = *((struct wmab_ret *) obj->buffer.pointer);
>       } else {
> +             kfree(out.pointer);
>               return AE_ERROR;
>       }
>  
> @@ -607,15 +609,22 @@ static acpi_status AMW0_set_capabilities(void)
>       args.ebx = 2 << 8;
>       args.ebx |= ACER_AMW0_BLUETOOTH_MASK;
>  
> +     /*
> +      * It's ok to use existing buffer for next wmab_execute call.
> +      * But we need to kfree(out.pointer) if next wmab_execute fail.
> +      */
>       status = wmab_execute(&args, &out);
> -     if (ACPI_FAILURE(status))
> +     if (ACPI_FAILURE(status)) {
> +             kfree(out.pointer);
>               return status;
> +     }
>  
>       obj = (union acpi_object *) out.pointer;
>       if (obj && obj->type == ACPI_TYPE_BUFFER
>       && obj->buffer.length == sizeof(struct wmab_ret)) {
>               ret = *((struct wmab_ret *) obj->buffer.pointer);
>       } else {
> +             kfree(out.pointer);
>               return AE_ERROR;
>       }
>  

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