Re: [PATCH] x86/sgx: fix a NULL pointer

On 7/17/23 13:29, Haitao Huang wrote:

Under heavy load, the SGX EPC reclaimers (current ksgxd or future EPC cgroup worker) may reclaim the SECS EPC page for an enclave and set encl->secs.epc_page to NULL. But the SECS EPC page is used for EAUG in the SGX #PF handler without checking for NULL and reloading.

Fix this by checking if SECS is loaded before EAUG and load it if it was reclaimed.

It would be nice to see a _bit_ more theory of the bug in here.

What is an SECS page and why is it special in a reclaim context? Why is this so hard to hit? What led you to discover this issue now? What is EAUG?