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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>,
	Steven Rostedt <srostedt@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	David Howells <dhowells@redhat.com>
Subject: Re: __update_max_tr: rcu_read_lock() used illegally while idle!
Date: Tue, 31 Jul 2012 11:21:14 -0700	[thread overview]
Message-ID: <20120731182114.GN2422@linux.vnet.ibm.com> (raw)
In-Reply-To: <1343758001.27983.66.camel@gandalf.stny.rr.com>

On Tue, Jul 31, 2012 at 02:06:41PM -0400, Steven Rostedt wrote:
> On Tue, 2012-07-31 at 10:44 -0700, Paul E. McKenney wrote:
> 
> > OK, I interpret this as excluding NMI handlers, but please let me
> > know if I am still being naive.  ;-)
> > 
> 
> You are correct. This is only called where lockdep is called (to trace
> enabling of IRQS). Note, that its called before normal irqs are actually
> enabled (interrupts are still disabled), this is why it's called outside
> of the in_irq() sections, because it is called just before returning
> back to process context.
> 
> That said, because NMIs are so difficult, lockdep doesn't record the
> disabling (and then enabling) of interrupts when an NMI triggers. Thus,
> the irqsoff tracer also does not record NMIs. Which is fine, because
> NMIs should not take long to run (we can add other mechanisms to time
> NMI length if that is needed), and NMIs should not be enabling
> interrupts nor taking any locks.
> 
> >From arch/x86/kernel/entry_64.S:
> 
> 	/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */

Then the patch on my earlier email should do it for you.

							Thanx, Paul


  reply	other threads:[~2012-07-31 18:22 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-24  9:03 __update_max_tr: rcu_read_lock() used illegally while idle! Fengguang Wu
2012-07-24  9:07 ` Testing tracer wakeup_rt: .. no entries found ..FAILED! Fengguang Wu
2012-07-25  1:31   ` Testing tracer wakeup: " Fengguang Wu
2012-07-30 15:45   ` Testing tracer wakeup_rt: " Steven Rostedt
2012-07-31 12:17     ` Fengguang Wu
2012-07-31 12:37       ` Avi Kivity
2012-07-31 12:43         ` Steven Rostedt
2012-07-31 12:50           ` Avi Kivity
2012-07-31 13:13             ` Steven Rostedt
2012-07-31 23:43               ` Fengguang Wu
2012-07-31 23:51                 ` Steven Rostedt
2012-07-31 23:57                   ` Paul E. McKenney
2012-08-01  0:09                     ` Steven Rostedt
2012-08-01  0:18                       ` Paul E. McKenney
2012-08-01  0:43                         ` pci_get_subsys: GFP_KERNEL allocations with IRQs disabled Fengguang Wu
2012-08-22  2:50                           ` Fengguang Wu
2012-08-22  7:49                             ` Feng Tang
2012-08-22 13:02                               ` Fengguang Wu
2012-08-22 18:02                               ` Bjorn Helgaas
2012-08-23  5:45                                 ` Feng Tang
2012-08-23  7:45                                 ` [PATCH 1/2] PCI: Use local parameter pci_device_id for pci_get_subsys/class() Feng Tang
2012-09-08  1:00                                   ` Yinghai Lu
2012-09-08  1:32                                     ` Yinghai Lu
2012-09-08  1:59                                       ` Greg Kroah-Hartman
2012-09-08 13:42                                       ` Fengguang Wu
2012-09-08 15:30                                         ` Yinghai Lu
2012-09-08 15:34                                         ` Feng Tang
2012-09-08 18:40                                           ` Yinghai Lu
2012-09-08 21:06                                             ` Bjorn Helgaas
2012-08-23  7:45                                 ` [PATCH 2/2] PCI: Remove the obsolete no_pci_devices() check Feng Tang
2012-07-31 23:57                   ` Testing tracer wakeup_rt: .. no entries found ..FAILED! Fengguang Wu
2012-08-07 13:29                     ` Steven Rostedt
2012-08-07 13:32                       ` Fengguang Wu
2012-08-21 15:16     ` [tip:perf/core] tracing: Fix wakeup_rt self test on virtual machines tip-bot for Steven Rostedt
2012-07-30 15:39 ` __update_max_tr: rcu_read_lock() used illegally while idle! Steven Rostedt
2012-07-31 12:05   ` Fengguang Wu
2012-07-31 12:10     ` Fengguang Wu
2012-07-31 13:44       ` Steven Rostedt
2012-07-31 14:41         ` Paul E. McKenney
2012-07-31 13:33     ` Steven Rostedt
2012-07-31 14:44       ` Paul E. McKenney
2012-07-31 14:51         ` Steven Rostedt
2012-07-31 14:56           ` Steven Rostedt
2012-07-31 15:18             ` Paul E. McKenney
2012-07-31 15:45               ` Steven Rostedt
2012-07-31 17:17                 ` Paul E. McKenney
2012-07-31 17:24                   ` Steven Rostedt
2012-07-31 17:44                     ` Paul E. McKenney
2012-07-31 18:06                       ` Steven Rostedt
2012-07-31 18:21                         ` Paul E. McKenney [this message]
2012-07-31 15:00           ` Paul E. McKenney

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