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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: linux-sgx@vger.kernel.org
Subject: Re: [PATCH] x86/sgx: WARN once if EREMOVE fails when killing an enclave
Date: Thu, 10 Oct 2019 11:56:07 -0700	[thread overview]
Message-ID: <20191010185607.GE23798@linux.intel.com> (raw)
In-Reply-To: <20191010183548.GD23798@linux.intel.com>

On Thu, Oct 10, 2019 at 11:35:48AM -0700, Sean Christopherson wrote:
> On Wed, Oct 09, 2019 at 03:04:50AM +0300, Jarkko Sakkinen wrote:
> > On Mon, Oct 07, 2019 at 09:13:34PM -0700, Sean Christopherson wrote:
> > > WARN if EREMOVE fails when destroying an enclave.  sgx_encl_release()
> > > uses the non-WARN __sgx_free_page() when freeing pages as some pages may
> > > be in the process of being reclaimed, i.e. are owned by the reclaimer.
> > > But EREMOVE should never fail as sgx_encl_destroy() is only called when
> > > the enclave cannot have active threads, e.g. prior to EINIT and when the
> > > enclave is being released.
> > > 
> > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > For me this concludes that I will manually convert all the call sites
> > to use __sgx_free_page() and add appropriate warnings. I agree with
> > Borislav's conclusions here.
> 
> Argh, now we have a bunch of call sites that can silently leak EPC pages,
> and I'm seeing timeouts during testing that strongly suggest pages are
> being leaked...

Confirmed that we're leaking pages, but it's not related to the -EBUSY
case in sgx_free_page().  Debug in progress...

As to the sgx_free_page() thing, I think we can invert the old WARN logic
and make everyone happy.  I'll send a patch.

  reply	other threads:[~2019-10-10 18:56 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-08  4:13 [PATCH] x86/sgx: WARN once if EREMOVE fails when killing an enclave Sean Christopherson
2019-10-08  4:15 ` Sean Christopherson
2019-10-09  0:04 ` Jarkko Sakkinen
2019-10-10 18:35   ` Sean Christopherson
2019-10-10 18:56     ` Sean Christopherson [this message]
2019-10-10 20:52       ` Sean Christopherson

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