On Fri, Sep 09, 2022 at 07:01:36AM +0300, Jarkko Sakkinen wrote:
On Thu, Sep 08, 2022 at 05:06:58PM -0700, Reinette Chatre wrote:
Hi Jarkko,
On 9/8/2022 4:19 PM, Jarkko Sakkinen wrote:
On Thu, Sep 08, 2022 at 03:43:06PM -0700, Reinette Chatre wrote:
Hi Jarkko and Haitao,
On 9/4/2022 7:04 PM, Jarkko Sakkinen wrote:
From: Haitao Huang haitao.huang@linux.intel.com
For EMODT and EREMOVE ioctl()'s with a large range, kernel may not finish in one shot and return EAGAIN error code and count of bytes of EPC pages on that operations are finished successfully.
Change the unclobbered_vdso_oversubscribed_remove test to rerun the ioctl()'s in a loop, updating offset and length using the byte count returned in each iteration.
Fixes: 6507cce561b4 ("selftests/sgx: Page removal stress test")
Should this patch be moved to the "critical fixes for v6.0" series?
I think not because it does not risk stability of the kernel itself. It's "nice to have" but not mandatory.
ok, thank you for considering it.
...
@@ -453,16 +454,30 @@ TEST_F_TIMEOUT(enclave, unclobbered_vdso_oversubscribed_remove, 900) modt_ioc.offset = heap->offset; modt_ioc.length = heap->size; modt_ioc.page_type = SGX_PAGE_TYPE_TRIM;
- count = 0; TH_LOG("Changing type of %zd bytes to trimmed may take a while ...", heap->size);
- ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_MODIFY_TYPES, &modt_ioc);
- errno_save = ret == -1 ? errno : 0;
- do {
ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_MODIFY_TYPES, &modt_ioc);errno_save = ret == -1 ? errno : 0;if (errno_save != EAGAIN)break;EXPECT_EQ(modt_ioc.result, 0);If this check triggers then there is something seriously wrong and in that case it may also be that this loop may be unable to terminate or the error condition would keep appearing until the loop terminates (which may be many iterations). Considering the severity and risk I do think that ASSERT_EQ() would be more appropriate, similar to how ASSERT_EQ() is used in patch 5/5.
Apart from that I think that this looks good.
Thank you very much for adding this.
Reinette
Hmm... I could along the lines:
/*
- Get time since Epoch is milliseconds.
*/ unsigned long get_time(void) { struct timeval start;
gettimeofday(&start, NULL); return (unsigneg long)start.tv_sec * 1000L + (unsigned long)start.tv_usec / 1000L;}
and
#define IOCTL_RETRY_TIMEOUT 100
In the test function:
unsigned long start_time; /* ... */ start_time = get_time(); do { EXPECT_LT(get_time() - start_time(), IOCTL_RETRY_TIMEOUT); /* ... */ } /* ... */What do you think?
I do think that your proposal can be considered for an additional check in this test but the way I understand it it does not address my feedback.
In this patch the flow is:
do { ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_MODIFY_TYPES, &modt_ioc);
errno_save = ret == -1 ? errno : 0; if (errno_save != EAGAIN) break; EXPECT_EQ(modt_ioc.result, 0); ...} while ...
If this EXPECT_EQ() check fails then it means that errno_save is EAGAIN and modt_ioc.result != 0. This should never happen because in the kernel (sgx_enclave_modify_types()) the only time modt_ioc.result can be set is when the ioctl() returns EFAULT.
In my opinion this check should be changed to: ASSERT_EQ(modt_ioc.result, 0);
Right, I missed this. It should be definitely ASSERT_EQ(().
I was thinking to add patch, which adds helper to calculate static content length from the last item of the segment table (offset + size) and replace total_length calculations in various tests.
I won't send a new version this week because I'm at Open Source Summit EU and Linux Security Summit EU.
BR, Jarkko