From: Steven Rostedt <rostedt@goodmis.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: There is a Tasks RCU stall warning
Date: Tue, 11 Apr 2017 17:31:33 -0400 [thread overview]
Message-ID: <20170411173133.52b28cfe@gandalf.local.home> (raw)
In-Reply-To: <20170411211802.GA19165@linux.vnet.ibm.com>
On Tue, 11 Apr 2017 14:18:02 -0700
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> Hello, Steve,
>
> Network connectivity issues... :-/
>
> There is already a Tasks RCU stall warning, but it waits for
> ten -minutes- before complaining. You can change this with the
> rcupdate.rcu_task_stall_timeout kernel boot parameter, if you wish.
>
> Or did you wait longer than ten minutes?
>
Remember when I said I had a bunch of debugging turned on in this
kernel. Well, I also included my ftrace trace_event benchmark code.
Which appears to be what is triggering this.
[ 205.159860] INFO: rcu_tasks detected stalls on tasks:
[ 205.165042] ffff8800c40450c0: .. nvcsw: 2/2 holdout: 1 idle_cpu: -1/1
[ 205.171627] event_benchmark R running task 30224 1113 2 0x10000000
[ 205.178829] Call Trace:
[ 205.181379] __schedule+0x574/0x1210
[ 205.185061] ? __schedule+0x574/0x1210
[ 205.188917] ? mark_held_locks+0x23/0xc0
[ 205.192944] ? mark_held_locks+0x23/0xc0
[ 205.196964] ? retint_kernel+0x2d/0x2d
[ 205.200831] ? retint_kernel+0x2d/0x2d
[ 205.204679] ? trace_hardirqs_on_caller+0x182/0x280
[ 205.209660] ? trace_hardirqs_on_thunk+0x1a/0x1c
[ 205.214380] ? trace_hardirqs_on_thunk+0x1a/0x1c
[ 205.219097] irq_exit+0x91/0x100
[ 205.222418] ? retint_kernel+0x2d/0x2d
[ 205.226263] ? retint_kernel+0x2d/0x2d
[ 205.230113] ? kthread_should_stop+0x3d/0x60
[ 205.234486] ? __asan_load8+0x11/0x70
[ 205.238245] ? ring_buffer_record_is_on+0x11/0x20
[ 205.243052] ? tracing_is_on+0x15/0x30
[ 205.246895] ? benchmark_event_kthread+0x4f/0x3c0
[ 205.251708] ? kthread+0x178/0x1d0
[ 205.255200] ? trace_benchmark_reg+0x80/0x80
[ 205.259563] ? kthread_create_on_node+0xa0/0xa0
[ 205.264205] ? ret_from_fork+0x2e/0x40
The thread gets created when I enable the benchmark tracepoint. It just
so happens that my test enables *all* tracepoints, which would of
course include this one as well.
I'll have to look at this code to see why it is getting missed.
-- Steve
next prev parent reply other threads:[~2017-04-11 21:31 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-11 21:18 There is a Tasks RCU stall warning Paul E. McKenney
2017-04-11 21:21 ` Steven Rostedt
2017-04-11 21:32 ` Paul E. McKenney
2017-04-11 21:31 ` Steven Rostedt [this message]
2017-04-11 21:34 ` Steven Rostedt
2017-04-11 21:39 ` Steven Rostedt
2017-04-11 21:44 ` Paul E. McKenney
2017-04-11 21:49 ` Steven Rostedt
2017-04-11 21:56 ` Paul E. McKenney
2017-04-11 22:15 ` Steven Rostedt
2017-04-11 23:01 ` Paul E. McKenney
2017-04-11 23:04 ` Paul E. McKenney
2017-04-11 23:11 ` Paul E. McKenney
2017-04-12 3:23 ` Paul E. McKenney
2017-04-12 13:18 ` Steven Rostedt
2017-04-12 14:19 ` Paul E. McKenney
2017-04-12 14:42 ` Steven Rostedt
2017-04-12 15:18 ` Paul E. McKenney
2017-04-12 15:53 ` Steven Rostedt
2017-04-12 16:26 ` Paul E. McKenney
2017-04-12 16:49 ` Steven Rostedt
2017-04-12 14:48 ` Paul E. McKenney
2017-04-12 14:59 ` Steven Rostedt
2017-04-12 16:27 ` Paul E. McKenney
2017-04-12 16:57 ` Steven Rostedt
2017-04-12 17:07 ` Paul E. McKenney
2017-04-12 17:13 ` Steven Rostedt
2017-04-12 20:02 ` Paul E. McKenney
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