On Fri Oct 20, 2023 at 5:53 AM EEST, Haitao Huang wrote:
> In the EAUG on page fault path, VM_FAULT_OOM is returned when the
> Enclave Page Cache (EPC) runs out. This may trigger unneeded OOM kill
> that will not free any EPCs. Return VM_FAULT_SIGBUS instead.
>
> Fixes: 5a90d2c3f5ef ("x86/sgx: Support adding of pages to an initialized
> enclave")
> Cc: [email protected] # v6.0+
> Signed-off-by: Haitao Huang <[email protected]>
> ---
> arch/x86/kernel/cpu/sgx/encl.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> index 279148e72459..d13b7e4ad0f5 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.c
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -322,7 +322,7 @@ struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl
> *encl,
> * ENCLS[EAUG] instruction.
> *
> * Returns: Appropriate vm_fault_t: VM_FAULT_NOPAGE when PTE was installed
> - * successfully, VM_FAULT_SIGBUS or VM_FAULT_OOM as error otherwise.
> + * successfully, VM_FAULT_SIGBUS as error otherwise.
> */
> static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
> struct sgx_encl *encl, unsigned long addr)
> @@ -348,7 +348,7 @@ static vm_fault_t sgx_encl_eaug_page(struct
> vm_area_struct *vma,
> secinfo_flags = SGX_SECINFO_R | SGX_SECINFO_W | SGX_SECINFO_X;
> encl_page = sgx_encl_page_alloc(encl, addr - encl->base, secinfo_flags);
> if (IS_ERR(encl_page))
> - return VM_FAULT_OOM;
> + return VM_FAULT_SIGBUS;
>
> mutex_lock(&encl->lock);
>
Reviewed-by: Jarkko Sakkinen <[email protected]>
BR, Jarkko
