From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: rcu warnings cause stack overflow
Date: Thu, 2 Feb 2012 13:27:42 +0100 [thread overview]
Message-ID: <20120202122742.GA2745@osiris.boeblingen.de.ibm.com> (raw)
In-Reply-To: <20120201151445.GA6731@somewhere.redhat.com>
On Wed, Feb 01, 2012 at 04:14:48PM +0100, Frederic Weisbecker wrote:
> > Removing the WARN_ON_ONCE will fix this and, if lockdep is turned on, still
> > will find illegal uses. But it won't work for lockdep off configs...
> > So we probably want something better than the patch below.
>
> Ah ok. Hmm, but why are you using an exception to implement WARN_ON()
> in s390? Is it to have a whole new stack for the warning path in order
> to avoid stack overflow from the place that called the WARN_ON() ?
The reason was to reduce the code footprint of the WARN_ON() and also
be able to print the register contents at the time the warning happened.
All architectures which define __WARN_TAINT implement warnings with
exceptions. Currently that are parisc, powerpc, s390 and sh.
next prev parent reply other threads:[~2012-02-02 12:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-01 10:06 rcu warnings cause stack overflow Heiko Carstens
2012-02-01 15:14 ` Frederic Weisbecker
2012-02-01 17:18 ` Paul E. McKenney
2012-02-01 18:08 ` Frederic Weisbecker
2012-02-01 18:22 ` Paul E. McKenney
2012-02-01 18:31 ` Frederic Weisbecker
2012-02-02 12:27 ` Heiko Carstens [this message]
2012-02-02 14:52 ` Frederic Weisbecker
2012-02-02 19:11 ` Paul E. McKenney
2012-02-03 9:32 ` Heiko Carstens
2012-02-03 18:33 ` Paul E. McKenney
2012-02-04 13:13 ` Frederic Weisbecker
2012-02-04 16:52 ` Paul E. McKenney
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