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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
	x86@kernel.org, platform-driver-x86@vger.kernel.org,
	linux-sgx@vger.kernel.org, nhorman@redhat.com,
	npmccallum@redhat.com, serge.ayoun@intel.com,
	shay.katz-zamir@intel.com, haitao.huang@linux.intel.com,
	andriy.shevchenko@linux.intel.com, tglx@linutronix.de,
	kai.svahn@intel.com, mark.shanahan@intel.com,
	luto@amacapital.net, Suresh Siddha <suresh.b.siddha@intel.com>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Darren Hart <dvhart@infradead.org>,
	Andy Shevchenko <andy@infradead.org>,
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v17 18/23] platform/x86: Intel SGX driver
Date: Mon, 17 Dec 2018 21:33:22 +0200
Message-ID: <20181217193322.GA29785@linux.intel.com> (raw)
In-Reply-To: <20181217184858.GF12491@linux.intel.com>

On Mon, Dec 17, 2018 at 10:48:58AM -0800, Sean Christopherson wrote:
> On Mon, Dec 17, 2018 at 08:43:33PM +0200, Jarkko Sakkinen wrote:
> > On Mon, Dec 17, 2018 at 10:36:13AM -0800, Sean Christopherson wrote:
> > > I'm pretty sure doing mmget() would result in circular dependencies and
> > > a zombie enclave.  In the do_exit() case where a task is abruptly killed:
> > >  
> > >   - __mmput() is never called because the enclave holds a ref
> > >   - sgx_encl_release() is never be called because its VMAs hold refs
> > >   - sgx_vma_close() is never called because __mmput()->exit_mmap() is
> > >     blocked and the process itself is dead, i.e. won't unmap anything.
> > 
> > Right, it does, you are absolutely right. Tried it and removed the
> > commit already.
> > 
> > Well, what we came up from your suggestion i.e. setting mm to NULL
> > and checking that is very subtle change and does not have any such
> > circular dependencies. We'll go with that.
> 
> We can't set mm to NULL as we need it to unregister the notifier, and
> I'm fairly certain attempting to unregister in the release callback
> will deadlock.

Noticed that too. mmu_notifier_unregister() requires a valid mm.

/Jarkko

  parent reply index

Thread overview: 161+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20181116010412.23967-1-jarkko.sakkinen@linux.intel.com>
2018-11-16  1:01 ` [PATCH v17 01/23] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2018-11-16 14:22   ` Borislav Petkov
2018-11-16 15:07     ` Jarkko Sakkinen
2018-11-16 20:24       ` Borislav Petkov
2018-11-18  8:20         ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 02/23] x86/cpufeatures: Add Intel-defined SGX feature bit Jarkko Sakkinen
2018-11-16 14:28   ` Borislav Petkov
2018-11-16 15:13     ` Jarkko Sakkinen
2018-11-16 15:18       ` Jarkko Sakkinen
2018-11-16 20:53         ` Borislav Petkov
2018-11-16  1:01 ` [PATCH v17 03/23] x86/cpufeatures: Add SGX sub-features (as Linux-defined bits) Jarkko Sakkinen
2018-11-16 14:37   ` Borislav Petkov
2018-11-16 15:38     ` Sean Christopherson
2018-11-16 23:31   ` Dave Hansen
2018-11-18  8:36     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 04/23] x86/msr: Add IA32_FEATURE_CONTROL.SGX_ENABLE definition Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 05/23] x86/cpufeatures: Add Intel-defined SGX_LC feature bit Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 06/23] x86/cpu/intel: Detect SGX support and update caps appropriately Jarkko Sakkinen
2018-11-16 23:32   ` Dave Hansen
2018-11-18  8:37     ` Jarkko Sakkinen
2018-11-21 18:17   ` Borislav Petkov
2018-11-24 13:54     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 07/23] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen
2018-11-16 23:33   ` Dave Hansen
2018-11-18  8:38     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 08/23] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 09/23] x86/sgx: Define SGX1 and SGX2 ENCLS leafs Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 10/23] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 11/23] x86/sgx: Add SGX1 and SGX2 architectural data structures Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 12/23] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 13/23] x86/msr: Add SGX Launch Control MSR definitions Jarkko Sakkinen
2018-11-16 17:29   ` Sean Christopherson
2018-11-18  8:19     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 14/23] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 15/23] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 16/23] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 17/23] x86/sgx: Add sgx_einit() for initializing enclaves Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 18/23] platform/x86: Intel SGX driver Jarkko Sakkinen
2018-11-16  1:37   ` Randy Dunlap
2018-11-16 11:23     ` Jarkko Sakkinen
2018-11-19 15:06   ` Jarkko Sakkinen
2018-11-19 16:22     ` Jethro Beekman
2018-11-19 17:19       ` Jarkko Sakkinen
2018-11-19 17:39         ` Jethro Beekman
2018-11-20 10:58           ` Jarkko Sakkinen
2018-11-21 15:24             ` Jarkko Sakkinen
2018-11-19 18:18         ` Andy Lutomirski
2018-11-20 11:00           ` Jarkko Sakkinen
2018-11-19 15:29   ` Andy Lutomirski
2018-11-19 16:19     ` Jarkko Sakkinen
2018-11-19 16:59       ` Andy Lutomirski
2018-11-20 12:04         ` Jarkko Sakkinen
2018-11-22 11:12           ` Dr. Greg
2018-11-22 15:21             ` Andy Lutomirski
2018-11-24 17:21               ` Jarkko Sakkinen
2018-11-24 20:13                 ` Dr. Greg
2018-11-26 21:15                   ` Jarkko Sakkinen
2018-11-25 14:53                 ` Jarkko Sakkinen
2018-11-25 16:22                   ` Andy Lutomirski
2018-11-25 18:55                     ` Dr. Greg
2018-11-25 23:51                       ` Jarkko Sakkinen
     [not found]                       ` <D45BC005-5064-4C75-B486-4E43C454E2F6@amacapital.net>
2018-11-26  0:37                         ` Andy Lutomirski
2018-11-26 11:00                           ` Dr. Greg
2018-11-26 18:22                             ` Andy Lutomirski
2018-11-26 22:16                             ` Jarkko Sakkinen
2018-11-26 21:51                     ` Jarkko Sakkinen
2018-11-26 23:04                       ` Jarkko Sakkinen
2018-11-27  8:55                         ` Dr. Greg
2018-11-27 16:41                           ` Jarkko Sakkinen
2018-11-27 17:55                             ` Andy Lutomirski
2018-11-28 10:49                               ` Dr. Greg
2018-11-28 19:22                                 ` Jarkko Sakkinen
2018-12-10 10:49                                   ` Dr. Greg
2018-12-12 18:00                                     ` Jarkko Sakkinen
2018-12-14 23:59                                       ` Dr. Greg
2018-12-15  0:06                                         ` Sean Christopherson
2018-12-15 23:22                                           ` Dr. Greg
2018-12-17 14:27                                             ` Sean Christopherson
2018-12-17 13:28                                           ` Jarkko Sakkinen
2018-12-17 13:39                                             ` Jarkko Sakkinen
2018-12-17 14:08                                               ` Jarkko Sakkinen
2018-12-17 14:13                                                 ` Jarkko Sakkinen
2018-12-17 16:34                                                   ` Dr. Greg
2018-12-17 17:31                                                 ` Sean Christopherson
2018-12-17 17:49                                                   ` Jarkko Sakkinen
2018-12-17 18:09                                                     ` Sean Christopherson
2018-12-17 18:23                                                       ` Jarkko Sakkinen
2018-12-17 18:46                                                         ` Sean Christopherson
2018-12-17 19:36                                                           ` Jarkko Sakkinen
2018-11-27 16:46                           ` Jarkko Sakkinen
2018-11-28 21:52                           ` Andy Lutomirski
2018-11-27  7:46                       ` Jethro Beekman
2018-11-27 16:36                         ` Jarkko Sakkinen
2018-11-22 20:56             ` Andy Lutomirski
2018-11-23 10:39               ` Dr. Greg
2018-11-24 16:45                 ` Jarkko Sakkinen
2018-11-28  5:08                   ` Jarkko Sakkinen
2018-11-28  5:38                     ` Jethro Beekman
2018-12-09 17:01         ` Pavel Machek
2018-11-20 11:15     ` Dr. Greg
2018-11-24 16:15       ` Jarkko Sakkinen
2018-11-24 19:24         ` Dr. Greg
2018-11-26 19:39           ` Jarkko Sakkinen
2018-12-09 17:01     ` Pavel Machek
2018-12-10 14:46       ` Dr. Greg
2018-12-17 17:45   ` Dave Hansen
2018-12-17 18:01     ` Jarkko Sakkinen
2018-12-17 18:07       ` Dave Hansen
2018-12-17 18:31         ` Jarkko Sakkinen
2018-12-17 18:36       ` Sean Christopherson
2018-12-17 18:43         ` Jarkko Sakkinen
2018-12-17 18:47           ` Dave Hansen
2018-12-17 19:12             ` Andy Lutomirski
2018-12-17 19:17               ` Dave Hansen
2018-12-17 19:25                 ` Andy Lutomirski
2018-12-17 19:54                   ` Jarkko Sakkinen
2018-12-17 19:49                 ` Jarkko Sakkinen
2018-12-17 19:53                   ` Dave Hansen
2018-12-17 19:55                     ` Andy Lutomirski
2018-12-17 20:03                       ` Dave Hansen
2018-12-17 20:10                         ` Andy Lutomirski
2018-12-17 20:15                           ` Dave Hansen
2018-12-17 22:36                             ` Sean Christopherson
2018-12-18  1:40                           ` Jarkko Sakkinen
2018-12-17 22:20               ` Sean Christopherson
2018-12-18  1:39                 ` Jarkko Sakkinen
2018-12-18  3:27                   ` Jarkko Sakkinen
2018-12-18  5:02                     ` Andy Lutomirski
2018-12-18 13:27                       ` Jarkko Sakkinen
2018-12-18  4:55                   ` Andy Lutomirski
2018-12-18 13:18                     ` Jarkko Sakkinen
2018-12-18  4:59                 ` Andy Lutomirski
2018-12-18 13:11                   ` Jarkko Sakkinen
2018-12-18 15:44                   ` Sean Christopherson
2018-12-18 18:53                     ` Sean Christopherson
2018-12-19  5:00                       ` Jarkko Sakkinen
2018-12-19  5:13                         ` Jarkko Sakkinen
2018-12-21 18:28                         ` Sean Christopherson
2018-12-22  0:01                           ` Jarkko Sakkinen
2018-12-19  4:47                     ` Jarkko Sakkinen
2018-12-19  5:24                       ` Jarkko Sakkinen
2018-12-18  1:17               ` Jarkko Sakkinen
2018-12-18  1:31                 ` Jarkko Sakkinen
2018-12-17 18:48           ` Sean Christopherson
2018-12-17 19:09             ` Dave Hansen
2018-12-17 19:37               ` Jarkko Sakkinen
2018-12-17 19:40                 ` Dave Hansen
2018-12-17 19:33             ` Jarkko Sakkinen [this message]
2018-12-17 20:21               ` Jarkko Sakkinen
2018-12-18 13:13                 ` Jarkko Sakkinen
2018-12-18 15:46                   ` Sean Christopherson
2018-12-18  5:55   ` Andy Lutomirski
2018-12-19  5:22     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 19/23] platform/x86: sgx: Add swapping functionality to the " Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 20/23] x86/sgx: Add a simple swapper for the EPC memory manager Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 21/23] platform/x86: ptrace() support for the SGX driver Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 22/23] x86/sgx: SGX documentation Jarkko Sakkinen
2018-12-03  3:28   ` Randy Dunlap
2018-12-03  9:32     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 23/23] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2018-11-16 11:17 ` [PATCH v17 00/23] Intel SGX1 support Jarkko Sakkinen

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