On Mon, Oct 11, 2021, Tony Luck wrote:
> + section = &sgx_epc_sections[page->section];
> + node = section->node;
> +
> + spin_lock(&node->lock);
> +
> + /* Already poisoned? Nothing more to do */
> + if (page->poison)
> + goto out;
> +
> + page->poison = 1;
> +
> + /*
> + * If flags is zero, then the page is on a free list.
> + * Move it to the poison page list.
> + */
> + if (!page->flags) {
If the flag is inverted, this becomes
if (page->flags & SGX_EPC_PAGE_FREE) {
> + list_del(&page->list);
> + list_add(&page->list, &sgx_poison_page_list);
list_move(), and needs the same protection for sgx_poison_page_list.
> + goto out;
> + }
> +
> + /*
> + * TBD: Add additional plumbing to enable pre-emptive
> + * action for asynchronous poison notification. Until
> + * then just hope that the poison:
> + * a) is not accessed - sgx_free_epc_page() will deal with it
> + * when the user gives it back
> + * b) results in a recoverable machine check rather than
> + * a fatal one
> + */
> +out:
> + spin_unlock(&node->lock);
> + return 0;
> +}
> +
> /**
> * A section metric is concatenated in a way that @low bits 12-31 define the
> * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the
>
> --
> 2.31.1
>
