From: Borislav Petkov <bp@alien8.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>,
Andrea Parri <andrea.parri@amarulasolutions.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
Alan Stern <stern@rowland.harvard.edu>,
Will Deacon <will.deacon@arm.com>,
Boqun Feng <boqun.feng@gmail.com>,
Nicholas Piggin <npiggin@gmail.com>,
David Howells <dhowells@redhat.com>,
Jade Alglave <j.alglave@ucl.ac.uk>,
Luc Maranget <luc.maranget@inria.fr>,
Akira Yokosawa <akiyks@gmail.com>,
Daniel Lustig <dlustig@nvidia.com>
Subject: Re: [RFC PATCH] tools/memory-model: Remove (dep ; rfi) from ppo
Date: Tue, 26 Feb 2019 12:38:13 +0100 [thread overview]
Message-ID: <20190226113813.GA14753@zn.tnic> (raw)
In-Reply-To: <20190226113008.GI32534@hirez.programming.kicks-ass.net>
On Tue, Feb 26, 2019 at 12:30:08PM +0100, Peter Zijlstra wrote:
> When I used the argc variant, gcc-8 'works', but with s/argc/1/ it is
> still broken.
As requested on IRC:
$ gcc --version
gcc (SUSE Linux) 4.8.5
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ cat ptr.c
#include <stdio.h>
#include <string.h>
int y = 2, x = 1;
int main (int argc, char **argv) {
int *p = &x + 1;
int *q = &y;
printf("p=%p q=%p\n", p, q);
if (!memcmp(&p, &q, sizeof(p))) {
*p = 11;
printf("x=%d y=%d *p=%d *q=%d\n", x, y, *p, *q);
$ gcc -O2 -fno-strict-aliasing -o ptr ptr.c ; ./ptr
p=0x601044 q=0x601044
x=1 y=2 *p=11 *q=2
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2019-02-26 11:38 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-19 22:57 [RFC PATCH] tools/memory-model: Remove (dep ; rfi) from ppo Andrea Parri
2019-02-19 22:57 ` Andrea Parri
2019-02-20 2:01 ` Paul E. McKenney
2019-02-20 2:01 ` Paul E. McKenney
2019-02-20 9:26 ` Peter Zijlstra
2019-02-20 9:26 ` Peter Zijlstra
2019-02-20 9:57 ` Will Deacon
2019-02-20 9:57 ` Will Deacon
2019-02-20 13:17 ` Andrea Parri
2019-02-20 13:17 ` Andrea Parri
2019-02-20 13:14 ` Andrea Parri
2019-02-20 13:14 ` Andrea Parri
2019-02-20 13:27 ` Peter Zijlstra
2019-02-20 13:27 ` Peter Zijlstra
2019-02-22 11:21 ` Andrea Parri
2019-02-22 11:21 ` Andrea Parri
2019-02-22 13:00 ` Peter Zijlstra
2019-02-22 13:00 ` Peter Zijlstra
2019-02-25 17:55 ` Paul E. McKenney
2019-02-25 17:55 ` Paul E. McKenney
2019-02-26 9:21 ` Peter Zijlstra
2019-02-26 9:21 ` Peter Zijlstra
2019-02-26 9:30 ` Peter Zijlstra
2019-02-26 9:30 ` Peter Zijlstra
2019-02-26 10:45 ` Peter Zijlstra
2019-02-26 10:45 ` Peter Zijlstra
2019-02-26 11:21 ` Peter Zijlstra
2019-02-26 11:21 ` Peter Zijlstra
2019-02-26 11:25 ` Peter Zijlstra
2019-02-26 11:25 ` Peter Zijlstra
2019-02-26 11:30 ` Peter Zijlstra
2019-02-26 11:30 ` Peter Zijlstra
2019-02-26 11:38 ` Borislav Petkov [this message]
2019-02-26 11:38 ` Borislav Petkov
2019-02-26 13:49 ` Peter Zijlstra
2019-02-26 13:49 ` Peter Zijlstra
2019-02-26 14:28 ` Paul E. McKenney
2019-02-26 14:28 ` Paul E. McKenney
2019-02-26 14:47 ` Peter Zijlstra
2019-02-26 14:47 ` Peter Zijlstra
2019-02-26 15:39 ` Paul E. McKenney
2019-02-26 15:39 ` Paul E. McKenney
2019-02-26 14:56 ` Akira Yokosawa
2019-02-26 14:56 ` Akira Yokosawa
2019-02-26 15:04 ` Paul E. McKenney
2019-02-26 15:04 ` Paul E. McKenney
2019-02-26 15:09 ` Akira Yokosawa
2019-02-26 15:09 ` Akira Yokosawa
2019-02-26 15:04 ` Peter Zijlstra
2019-02-26 15:04 ` Peter Zijlstra
2019-03-06 15:46 ` Akira Yokosawa
2019-03-06 15:46 ` Akira Yokosawa
2019-03-06 16:58 ` Peter Zijlstra
2019-03-06 16:58 ` Peter Zijlstra
2019-03-06 17:26 ` Paul E. McKenney
2019-03-06 17:26 ` Paul E. McKenney
2019-03-06 17:24 ` Paul E. McKenney
2019-03-06 17:24 ` Paul E. McKenney
2019-03-02 15:27 ` Akira Yokosawa
2019-03-02 15:27 ` Akira Yokosawa
2019-03-04 16:09 ` Paul E. McKenney
2019-03-04 16:09 ` Paul E. McKenney
2019-02-20 13:41 ` Will Deacon
2019-02-20 13:41 ` Will Deacon
2019-02-20 15:30 ` Alan Stern
2019-02-20 15:30 ` Alan Stern
2019-02-20 15:22 ` Alan Stern
2019-02-20 15:22 ` Alan Stern
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