Re: [PATCH] platform/x86: ISST: fix use after free problem in tpmi_sst_dev_remove()

[Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>]

Hi Su Hui,

On 20/05/24 07:49, Su Hui wrote:
> clang static checker (scan-build) warning:
> drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c:1614:24:
> Use of memory after it is freed.
>
> Using 'tpmi_sst->package_id' after releasing 'tpmi_sst' causes this
> problem. Change the order of releasing 'tpmi_sst' to fix this.

This is fixed by me already.
Ref: 
https://lore.kernel.org/all/9293c51c7d502843bfff90c5664be00bfe112e8d.camel@xxxxxxxxxxxxxxx/

Thanks,
Harshit
> Fixes: 9d1d36268f3d ("platform/x86: ISST: Support partitioned systems")
> Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx>
> ---
>   drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> index 7bac7841ff0a..7fa360073f6e 100644
> --- a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> +++ b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
> @@ -1610,8 +1610,8 @@ void tpmi_sst_dev_remove(struct auxiliary_device *auxdev)
>   	tpmi_sst->partition_mask_current &= ~BIT(plat_info->partition);
>   	/* Free the package instance when the all partitions are removed */
>   	if (!tpmi_sst->partition_mask_current) {
> -		kfree(tpmi_sst);
>   		isst_common.sst_inst[tpmi_sst->package_id] = NULL;
> +		kfree(tpmi_sst);
>   	}
>   	mutex_unlock(&isst_tpmi_dev_lock);
>   }