Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1493541

Re: [PATCH locking/Documentation 1/2] Add note of release-acquire store vulnerability

From Peter Zijlstra <peterz@infradead.org>
Newsgroups linux.kernel
Subject Re: [PATCH locking/Documentation 1/2] Add note of release-acquire store vulnerability
Date 2016-09-29 18:00 +0200
Message-ID <smLUB-5YJ-3@gated-at.bofh.it> (permalink)
References <smLUB-5YJ-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

On Thu, Sep 29, 2016 at 08:54:01AM -0700, Paul E. McKenney wrote:
> If two processes are related by a RELEASE+ACQUIRE pair, ordering can be
> broken if a third process overwrites the value written by the RELEASE
> operation before the ACQUIRE operation has a chance of reading it.
> This commit therefore updates the documentation to call this vulnerability
> out explicitly.
> 
> Reported-by: Alan Stern <stern@rowland.harvard.edu>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> +     However, please note that a chain of RELEASE+ACQUIRE pairs may be
> +     broken by a store by another thread that overwrites the RELEASE
> +     operation's store before the ACQUIRE operation's read.

This is the powerpc lwsync quirk, right? Where the barrier disappears
when it looses the store.

Or is there more to it? Its not entirely clear from the Changelog, which
I feel should describe the reason for the behaviour.

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-29 18:00 +0200
  Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Will Deacon <will.deacon@arm.com> - 2016-09-29 18:10 +0200
    Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-29 18:20 +0200
      Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-29 18:50 +0200
    Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-29 18:50 +0200
      Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Will Deacon <will.deacon@arm.com> - 2016-09-29 19:20 +0200
        Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-29 19:30 +0200
          Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-29 20:10 +0200
            Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-29 20:20 +0200
              Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-29 20:50 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-29 21:20 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Alan Stern <stern@rowland.harvard.edu> - 2016-09-29 21:40 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-29 22:30 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-30 11:00 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-30 11:10 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-30 12:00 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-30 14:20 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-30 15:00 +0200
                Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-30 15:40 +0200
          Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Boqun Feng <boqun.feng@gmail.com> - 2016-09-30 08:00 +0200
            Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Will Deacon <will.deacon@arm.com> - 2016-09-30 11:30 +0200
              Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-30 13:40 +0200
      Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-30 12:30 +0200
        Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-30 14:20 +0200
          Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability Peter Zijlstra <peterz@infradead.org> - 2016-09-30 14:50 +0200
            Re: [PATCH locking/Documentation 1/2] Add note of release-acquire  store vulnerability "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-09-30 15:20 +0200

csiph-web