From: Oliver Sang <oliver.sang@intel.com>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: <oe-lkp@lists.linux.dev>, <lkp@intel.com>,
<linux-kernel@vger.kernel.org>, <oliver.sang@intel.com>
Subject: Re: [paulmck-rcu:dev.2023.11.08a] [EXP locktorture] 1254a620b4: WARNING:at_kernel/rcu/tree_stall.h:#rcu_stall_chain_notifier_register
Date: Tue, 12 Dec 2023 15:43:44 +0800 [thread overview]
Message-ID: <ZXgPMLDAn5ZHqvT6@xsang-OptiPlex-9020> (raw)
In-Reply-To: <4be82070-4cd5-4f31-8eb4-b38853fad865@paulmck-laptop>
hi, Paul,
On Mon, Dec 11, 2023 at 08:26:12PM -0800, Paul E. McKenney wrote:
> On Tue, Dec 12, 2023 at 10:06:36AM +0800, Oliver Sang wrote:
> > hi, Paul,
> >
> > On Mon, Dec 11, 2023 at 08:59:16AM -0800, Paul E. McKenney wrote:
> > > On Thu, Dec 07, 2023 at 04:19:56PM +0800, kernel test robot wrote:
> > > >
> > > >
> > > > Hello,
> > > >
> > > > kernel test robot noticed "WARNING:at_kernel/rcu/tree_stall.h:#rcu_stall_chain_notifier_register" on:
> > > >
> > > > commit: 1254a620b4a3832e65ac01bcef769b99e34515b2 ("EXP locktorture: Add RCU CPU stall-warning notifier stub")
> > > > https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git dev.2023.11.08a
> > >
> > > Thank you for your testing efforts!
> > >
> > > This one is expected behavior by explicit request from Linus Torvalds.
> > > The concern is that people might use this hook without understanding
> > > the risks of losing RCU CPU stall warnings.
> > >
> > > One fix would be to never specify the rcupdate.rcu_cpu_stall_notifiers
> > > kernel boot parameter. Another would be to forgive this warning when
> > > that boot parameter was specified. Your choice! ;-)
> >
> > Thanks a lot for information!
> >
> > this commit (1254a620b4) is a test for this warning, am I right?
> > when this warning mechanism goes into upstream, do you want us still report
> > for similar cases? or we could just ignore them? Thanks!
>
> This 1254a620b4 ("EXP locktorture: Add RCU CPU stall-warning notifier
> stub") commit is a debug-only use of this facility that will never go
> upstream, as signified by the "EXP" at the beginning of the subject line.
>
> Or is there some better way than "EXP" to mark commits that are not
> intended for mainline?
>
> Thanx, Paul
>
sorry, seems I didn't state it very well. let me clarify.
the 'EXP' and "This not-for-mainline commit" is very good for us to know it
will not go into mainline.
what I asked is if this warning is triggered by other usages (not this
debug-only test), could we still ignore them by following below guidance you
gave us?
> > > One fix would be to never specify the rcupdate.rcu_cpu_stall_notifiers
> > > kernel boot parameter. Another would be to forgive this warning when
> > > that boot parameter was specified. Your choice! ;-)
next prev parent reply other threads:[~2023-12-12 7:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-07 8:19 kernel test robot
2023-12-11 16:59 ` Paul E. McKenney
2023-12-12 2:06 ` Oliver Sang
2023-12-12 4:26 ` Paul E. McKenney
2023-12-12 7:43 ` Oliver Sang [this message]
2023-12-12 14:43 ` Paul E. McKenney
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