From: Peter Zijlstra <peterz@infradead.org>
To: "Reshetova, Elena" <elena.reshetova@intel.com>
Cc: Liljestrand Hans <ishkamiel@gmail.com>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Greg KH <gregkh@linuxfoundation.org>,
Kees Cook <keescook@chromium.org>,
"will.deacon@arm.com" <will.deacon@arm.com>,
Boqun Feng <boqun.feng@gmail.com>,
David Windsor <dwindsor@gmail.com>,
"aik@ozlabs.ru" <aik@ozlabs.ru>,
"david@gibson.dropbear.id.au" <david@gibson.dropbear.id.au>
Subject: [kernel-hardening] Re: Conversion from atomic_t to refcount_t: summary of issues
Date: Fri, 16 Dec 2016 15:01:58 +0100 [thread overview]
Message-ID: <20161216140158.GS3107@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <2236FBA76BA1254E88B949DDB74E612B41C216AE@IRSMSX102.ger.corp.intel.com>
On Fri, Dec 16, 2016 at 12:10:21PM +0000, Reshetova, Elena wrote:
> Is it ok to add at least refcount_inc_if_zero() ?
Of course not.
> We already have refcount_dec_if_one(), reffcount_dec_not_one() and
> refcount_inc_not_zero(), so this one is the only missing one and would
> greatly help in couple of cases.
No, its absolutely insane. 0 means its freed, you cannot get another
reference at that point.
If you have code that relies on that, its broken.
next prev parent reply other threads:[~2016-12-16 14:01 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-28 11:56 [kernel-hardening] Conversion from atomic_t to refcount_t: summary of issues Reshetova, Elena
2016-11-28 12:13 ` [kernel-hardening] " Peter Zijlstra
2016-11-28 12:44 ` Peter Zijlstra
2016-11-28 12:48 ` Peter Zijlstra
2016-11-28 14:12 ` [kernel-hardening] " Reshetova, Elena
2016-11-29 3:19 ` [kernel-hardening] " Alexey Kardashevskiy
2016-11-29 9:31 ` Peter Zijlstra
2016-11-30 0:23 ` Alexey Kardashevskiy
2016-11-29 15:35 ` [kernel-hardening] " Reshetova, Elena
2016-11-29 15:47 ` Peter Zijlstra
2016-12-01 19:15 ` [kernel-hardening] " Peter Zijlstra
2016-12-01 21:31 ` David Windsor
2016-12-01 23:03 ` Peter Zijlstra
2016-12-01 23:20 ` Kees Cook
2016-12-01 23:29 ` David Windsor
2016-12-02 1:17 ` Boqun Feng
2016-12-02 20:25 ` David Windsor
2016-12-07 13:24 ` Peter Zijlstra
2016-12-07 19:03 ` David Windsor
2016-12-09 14:48 ` David Windsor
2016-12-07 13:36 ` Peter Zijlstra
2016-12-01 23:20 ` David Windsor
2016-12-07 13:21 ` Peter Zijlstra
2016-12-02 15:44 ` Liljestrand Hans
2016-12-02 16:14 ` Greg KH
2016-12-07 13:52 ` Peter Zijlstra
2016-12-07 15:59 ` David Windsor
2016-12-07 16:26 ` Peter Zijlstra
2016-12-07 16:31 ` David Windsor
2016-12-16 12:10 ` [kernel-hardening] " Reshetova, Elena
2016-12-16 14:01 ` Peter Zijlstra [this message]
2016-12-19 7:55 ` Reshetova, Elena
2016-12-19 10:12 ` [kernel-hardening] " Peter Zijlstra
2016-12-20 9:13 ` [kernel-hardening] " Reshetova, Elena
2016-12-20 9:30 ` [kernel-hardening] " Greg KH
2016-12-20 9:40 ` [kernel-hardening] " Reshetova, Elena
2016-12-20 9:51 ` [kernel-hardening] " Greg KH
2016-12-20 9:55 ` [kernel-hardening] " Reshetova, Elena
2016-12-20 10:26 ` [kernel-hardening] " Greg KH
2016-12-20 9:41 ` Peter Zijlstra
2016-12-20 9:58 ` [kernel-hardening] " Reshetova, Elena
2016-12-20 10:55 ` [kernel-hardening] " Liljestrand Hans
2016-12-20 13:13 ` Peter Zijlstra
2016-12-20 13:35 ` Reshetova, Elena
2016-12-20 15:20 ` Liljestrand Hans
2016-12-20 15:52 ` Peter Zijlstra
2017-01-10 14:58 ` Peter Zijlstra
2016-12-07 14:13 ` Peter Zijlstra
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