From: Segher Boessenkool <segher@kernel.crashing.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Joel Fernandes <joel@joelfernandes.org>,
Zhouyi Zhou <zhouzhouyi@gmail.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
rcu <rcu@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
lance@osuosl.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: Re: BUG : PowerPC RCU: torture test failed with __stack_chk_fail
Date: Mon, 24 Apr 2023 12:29:00 -0500 [thread overview]
Message-ID: <20230424172900.GR19790@gate.crashing.org> (raw)
In-Reply-To: <ZEagN1jJwg+rUzX4@boqun-archlinux>
On Mon, Apr 24, 2023 at 08:28:55AM -0700, Boqun Feng wrote:
> On Mon, Apr 24, 2023 at 10:13:51AM -0500, Segher Boessenkool wrote:
> > At what points can r13 change? Only when some particular functions are
> > called?
>
> r13 is the local paca:
>
> register struct paca_struct *local_paca asm("r13");
>
> , which is a pointer to percpu data.
Yes, it is a global register variable.
> So if a task schedule from one CPU to anotehr CPU, the value gets
> changed.
But the compiler does not see that something else changes local_paca (or
r13 some other way, via assembler code perhaps)? Or is there a compiler
bug?
If the latter is true:
Can you make a reproducer and open a GCC PR? <https://gcc.gnu.org/bugs/>
for how to get started doing that. We need *exact* code that shows the
problem, together with a compiler command line. So that we can
reproduce the problem. That is step 0 in figuring out what is going on,
and then maybe fixing the problem :-)
Segher
next prev parent reply other threads:[~2023-04-24 17:35 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-22 12:46 BUG : PowerPC RCU: torture test failed with __stack_chk_fail Zhouyi Zhou
2023-04-22 19:19 ` Joel Fernandes
2023-04-23 1:37 ` Zhouyi Zhou
2023-04-23 5:45 ` Zhouyi Zhou
2023-04-22 19:28 ` Joel Fernandes
2023-04-24 0:32 ` Boqun Feng
2023-04-24 4:00 ` Zhouyi Zhou
2023-04-24 13:14 ` Michael Ellerman
2023-04-24 15:13 ` Segher Boessenkool
2023-04-24 15:28 ` Boqun Feng
2023-04-24 17:29 ` Segher Boessenkool [this message]
2023-04-24 19:25 ` Boqun Feng
2023-04-24 18:55 ` Joel Fernandes
2023-04-25 10:13 ` Peter Zijlstra
2023-04-25 10:58 ` Zhouyi Zhou
2023-04-25 11:06 ` Joel Fernandes
2023-04-25 3:12 ` Zhouyi Zhou
2023-04-25 13:40 ` Christophe Leroy
2023-04-25 13:49 ` Zhouyi Zhou
2023-04-26 0:32 ` Joel Fernandes
2023-04-26 1:31 ` Zhouyi Zhou
2023-04-26 2:15 ` Joel Fernandes
2023-04-26 2:37 ` Zhouyi Zhou
2023-04-26 0:42 ` Joel Fernandes
2023-04-26 12:29 ` Michael Ellerman
2023-04-26 13:44 ` Joel Fernandes
2023-04-26 14:20 ` Peter Zijlstra
2023-04-26 14:45 ` Michael Ellerman
2023-04-28 10:35 ` Christophe Leroy
2023-04-25 10:59 ` Joel Fernandes
2023-04-25 11:53 ` Peter Zijlstra
2023-04-25 13:36 ` Christophe Leroy
2023-04-24 22:07 ` Michael Ellerman
2023-04-24 22:13 ` Zhouyi Zhou
2023-04-25 6:01 ` Zhouyi Zhou
2023-04-25 9:27 ` Zhouyi Zhou
2023-04-27 3:09 ` Michael Ellerman
2023-04-27 3:32 ` Zhouyi Zhou
2023-04-27 9:21 ` Zhouyi Zhou
2023-04-27 14:13 ` Michael Ellerman
2023-04-27 14:29 ` Zhouyi Zhou
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