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From: Shuah Khan <shuahkh@osg.samsung.com>
To: Dave Hansen <dave.hansen@intel.com>,
	Shuah Khan <shuah@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, stable@kernel.org, linuxram@us.ibm.com,
	tglx@linutronix.de, mpe@ellerman.id.au, mingo@kernel.org,
	akpm@linux-foundation.org, Shuah Khan <shuahkh@osg.samsung.com>,
	Shuah Khan <shuahkh@osg.samsung.com>
Subject: Re: [PATCH 1/9] x86, pkeys: do not special case protection key 0
Date: Mon, 26 Mar 2018 11:58:59 -0600	[thread overview]
Message-ID: <19a54db9-b0bd-5661-de2a-c5ee76e733d9@osg.samsung.com> (raw)
In-Reply-To: <b54257c2-138c-7ac9-8176-0dc4868093ef@intel.com>

On 03/26/2018 11:53 AM, Dave Hansen wrote:
> On 03/26/2018 10:47 AM, Shuah Khan wrote:
>>
>> Also what happens "pkey_free() pkey-0" - can you elaborate more on that
>> "silliness consequences"
> 
> It's just what happens if you free any other pkey that is in use: it
> might get reallocated later.  The most likely scenario is that you will
> get pkey-0 back from pkey_alloc(), you will set an access-disable or
> write-disable bit in PKRU for it, and your next stack access will SIGSEGV.
> 

Thanks. This will good information to include in the commit log.

-- Shuah

  reply	other threads:[~2018-03-26 17:59 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-26 17:27 [PATCH 0/9] [v2] x86, pkeys: two protection keys bug fixes Dave Hansen
2018-03-26 17:27 ` [PATCH 1/9] x86, pkeys: do not special case protection key 0 Dave Hansen
2018-03-26 17:47   ` Shuah Khan
2018-03-26 17:53     ` Dave Hansen
2018-03-26 17:58       ` Shuah Khan [this message]
2018-03-26 17:27 ` [PATCH 2/9] x86, pkeys, selftests: save off 'prot' for allocations Dave Hansen
2018-03-26 17:27 ` [PATCH 3/9] x86, pkeys, selftests: add a test for pkey 0 Dave Hansen
2018-03-26 17:27 ` [PATCH 4/9] x86, pkeys: override pkey when moving away from PROT_EXEC Dave Hansen
2018-04-07  0:09   ` Ram Pai
2018-04-07  0:47     ` Dave Hansen
2018-04-07  1:09       ` Ram Pai
2018-04-26 17:57         ` Dave Hansen
2018-04-30  7:51           ` Ram Pai
2018-04-30 16:36             ` Dave Hansen
2018-04-25 22:10   ` Shakeel Butt
2018-04-26  8:55     ` Thomas Gleixner
2018-04-26 18:17       ` Dave Hansen
2018-03-26 17:27 ` [PATCH 5/9] x86, pkeys, selftests: fix pointer math Dave Hansen
2018-03-26 17:27 ` [PATCH 6/9] x86, pkeys, selftests: fix pkey exhaustion test off-by-one Dave Hansen
2018-03-26 17:27 ` [PATCH 7/9] x86, pkeys, selftests: factor out "instruction page" Dave Hansen
2018-03-26 17:27 ` [PATCH 8/9] x86, pkeys, selftests: add allow faults on unknown keys Dave Hansen
2018-03-26 17:27 ` [PATCH 9/9] x86, pkeys, selftests: add PROT_EXEC test Dave Hansen
  -- strict thread matches above, loose matches on Subject: below --
2018-04-27 17:45 [PATCH 0/9] [v3] x86, pkeys: two protection keys bug fixes Dave Hansen
2018-04-27 17:45 ` [PATCH 1/9] x86, pkeys: do not special case protection key 0 Dave Hansen
2018-03-23 18:09 [PATCH 0/9] x86, pkeys: two protection keys bug fixes Dave Hansen
2018-03-23 18:09 ` [PATCH 1/9] x86, pkeys: do not special case protection key 0 Dave Hansen
2018-03-26 17:35   ` Ram Pai
2018-03-26 17:39     ` Dave Hansen
2018-03-27  2:27   ` Ram Pai
2018-03-27  4:11     ` Dave Hansen

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