From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Kees Cook <keescook@chromium.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
David Laight <David.Laight@aculab.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mingo@kernel.org" <mingo@kernel.org>,
"jiangshanlai@gmail.com" <jiangshanlai@gmail.com>,
"dipankar@in.ibm.com" <dipankar@in.ibm.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"mathieu.desnoyers@efficios.com" <mathieu.desnoyers@efficios.com>,
"josh@joshtriplett.org" <josh@joshtriplett.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"peterz@infradead.org" <peterz@infradead.org>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"dhowells@redhat.com" <dhowells@redhat.com>,
"edumazet@google.com" <edumazet@google.com>,
"fweisbec@gmail.com" <fweisbec@gmail.com>,
"oleg@redhat.com" <oleg@redhat.com>
Subject: Re: [PATCH tip/core/rcu 02/20] torture: Prepare scripting for shift from %p to %pK
Date: Sun, 10 Dec 2017 10:51:01 -0800 [thread overview]
Message-ID: <20171210185101.GI7829@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAHp75VcJKYnW2grD6jViNFU3z6+fJoTmqs+ZP3Xm6YB3C8ZH1Q@mail.gmail.com>
On Sun, Dec 10, 2017 at 02:52:49PM +0200, Andy Shevchenko wrote:
> On Mon, Dec 4, 2017 at 6:11 PM, Paul E. McKenney
> <paulmck@linux.vnet.ibm.com> wrote:
> > On Mon, Dec 04, 2017 at 02:13:38PM +0000, David Laight wrote:
> >> From: Paul E. McKenney
> >> > Sent: 04 December 2017 13:42
> >> > On Mon, Dec 04, 2017 at 12:32:30PM +0000, David Laight wrote:
> >> > > From: Paul E. McKenney
> >> > > > Sent: 01 December 2017 20:09
> >> > > >
> >> > > > Because %p prints "(null)" and %pK prints "0000000000000000" or (on
> >> > > > 32-bit systems) "00000000", this commit adjusts torture-test scripting
> >> > > > accordingly.
> >> > >
> >> > > Surely NULL v not-NULL is one bit of info that the message needs to contain?
> >> >
> >> > Indeed. So the script needs to check for the strings "00000000",
> >> > "0000000000000000", and "(null) in the console output". The "(null)"
> >> > is what "%p" prints for a NULL pointer, and the other two strings are
> >> > what "%pK" prints for a NULL pointer.
> >> >
> >> > Or am I missing your point?
> >>
> >> I was thinking that even %pK should print "(null)".
> >
> > That was my expectation, as in the need for this patch came as a
> > surprise to me.
> >
> >> Perhaps it should have printed a fixed, non-zero value for non-zero
> >> pointers.
> >
> > I must leave this to the people who have a dog in that contest. ;-)
>
> Since there is an ongoing discussion with security people near to %pK
> and alike, I added Kees and Linus to Cc list.
>
> The proposed change can be done easily, though I have no knowledge
> about possible implications.
One question I have is whether the patches to convert RCU to %pK are
even desirable at this point: https://lwn.net/Articles/737451/
If something like the patches in that article get to mainline, then
shouldn't I just drop RCU's %pK patches?
Thanx, Paul
next prev parent reply other threads:[~2017-12-10 18:51 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-01 20:08 [PATCH tip/core/rcu 0/20] Torture-test updates for v4.16 Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 01/20] torture: Suppress CPU stall warnings during shutdown ftrace dump Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 02/20] torture: Prepare scripting for shift from %p to %pK Paul E. McKenney
2017-12-04 12:32 ` David Laight
2017-12-04 13:42 ` Paul E. McKenney
2017-12-04 14:13 ` David Laight
2017-12-04 16:11 ` Paul E. McKenney
2017-12-10 12:52 ` Andy Shevchenko
2017-12-10 18:51 ` Paul E. McKenney [this message]
2017-12-10 20:39 ` Linus Torvalds
2017-12-10 21:47 ` Paul E. McKenney
2017-12-11 19:59 ` Kees Cook
2017-12-12 16:08 ` Paul E. McKenney
[not found] ` <87wp1sa55h.fsf@concordia.ellerman.id.au>
[not found] ` <CA+55aFxHdAX_ztDMUyXihhUv_eftntHecGUUaV3qAtGj_ZbKCg@mail.gmail.com>
2017-12-13 12:59 ` Long live %pK (was Re: [PATCH tip/core/rcu 02/20] torture: Prepare scripting for shift from %p to %pK) Michael Ellerman
2017-12-13 18:21 ` Linus Torvalds
2017-12-01 20:08 ` [PATCH tip/core/rcu 03/20] rcutorture: Change printk() %p to %pK Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 04/20] torture: Reduce #ifdefs for preempt_schedule() Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 05/20] rcutorture: Preempt RCU-preempt readers more vigorously Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 06/20] rcutorture/configinit: Fix build directory error message Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 07/20] rcutorture: Remove unused script, config2frag.sh Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 08/20] rcutorture/kvm.sh: Remove unused variable, `alldone` Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 09/20] rcutorture/kvm.sh: Use consistent help text for --qemu-args Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 10/20] rcutorture/kvm.sh: Support execution from any directory Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 11/20] rcutorture/kvm-recheck-*: Improve result directory readability check Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 12/20] rcutorture: Simplify logging Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 13/20] rcutorture: Simplify functions.sh include path Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 14/20] rcutorture/kvm-build.sh: Skip build directory check Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 15/20] torture: Place all torture-test modules in one MAINTAINERS group Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 16/20] locking/locktorture: Fix rwsem reader_delay Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 17/20] locking/locktorture: Fix num reader/writer corner cases Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 18/20] torture: Make stutter less vulnerable to compilers and races Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 19/20] torture: Eliminate torture_runnable and perf_runnable Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 20/20] torture: Save a line in stutter_wait(): while -> for Paul E. McKenney
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