Re: [PATCH for_v23 3/9] x86/sgx: Fix a memory leak in sgx_encl_destroy()

[Sean Christopherson <sean.j.christopherson@intel.com>]

On Thu, Oct 10, 2019 at 02:42:55PM -0700, Sean Christopherson wrote:
> Delete an enclave page's entry in the radix tree regardless of whether
> or not it has an associated EPC page.
> 
> Note, the reclaimer doesn't need the tree to reclaim EPC pages, i.e.
> it's safe to delete the tree entry even if sgx_free_page() fails.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/x86/kernel/cpu/sgx/encl.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> index ea21d3737a32..68ec8944692a 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.c
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -468,15 +468,14 @@ void sgx_encl_destroy(struct sgx_encl *encl)
>  
>  	radix_tree_for_each_slot(slot, &encl->page_tree, &iter, 0) {
>  		entry = *slot;
> -		if (entry->epc_page) {
> -			if (!sgx_free_page(entry->epc_page)) {
> -				encl->secs_child_cnt--;
> -				entry->epc_page = NULL;
> -			}
> -
> -			radix_tree_delete(&entry->encl->page_tree,
> -					  PFN_DOWN(entry->desc));
> +		if (entry->epc_page &&
> +		    !sgx_free_page(entry->epc_page)) {
> +			encl->secs_child_cnt--;
> +			entry->epc_page = NULL;
>  		}
> +
> +		radix_tree_delete(&entry->encl->page_tree,
> +				  PFN_DOWN(entry->desc));

Uh, just realized we're not freeing the entry itself.  That's obviously
not good.  I'll spin a v2 to fix this proper.

>  	}
>  
>  	if (!encl->secs_child_cnt && encl->secs.epc_page) {
> -- 
> 2.22.0
>