Re: rcu: frequent rcu lockups

Sasha Levin
2015-03-11T23:07:01Z

On 03/11/2015 07:01 PM, Paul E. McKenney wrote:
>> With the commit I didn't hit it yet, but I do see 4 different WARNings:
> I wish that I could say that I am surprised, but the sad fact is that
> I am still shaking the bugs out.

I have one more to add:

[ 93.330539] WARNING: CPU: 1 PID: 8 at kernel/rcu/tree_plugin.h:476 rcu_gp_kthread+0x1eaa/0x4dd0()
[ 93.333515] Modules linked in:
[ 93.334678] CPU: 1 PID: 8 Comm: rcu_preempt Tainted: G W 4.0.0-rc3-next-20150311-sasha-00035-g0a45b48-dirty #2052
[ 93.338402] ffff8800496f8000 00000000f3e72ee7 ffff880049ac7b28 ffffffff9ea97e89
[ 93.339495] 0000000000000000 0000000000000000 ffff880049ac7b78 ffffffff941e242a
[ 93.339495] ffffffffa1721038 ffffffff9433bf2a ffffffffa1721040 ffff8800a2822000
[ 93.339495] Call Trace:
[ 93.339495] [<ffffffff9ea97e89>] dump_stack+0x4f/0x7b
[ 93.339495] [<ffffffff941e242a>] warn_slowpath_common+0xca/0x130
[ 93.339495] [<ffffffff9433bf2a>] ? rcu_gp_kthread+0x1eaa/0x4dd0
[ 93.339495] [<ffffffff941e266a>] warn_slowpath_null+0x1a/0x20
[ 93.339495] [<ffffffff9433bf2a>] rcu_gp_kthread+0x1eaa/0x4dd0
[ 93.339495] [<ffffffff95f2346c>] ? plist_check_head+0x3c/0x50
[ 93.339495] [<ffffffff9433a080>] ? cond_synchronize_rcu+0x20/0x20
[ 93.339495] [<ffffffff942dffb5>] ? trace_hardirqs_on_caller+0x475/0x610
[ 93.339495] [<ffffffff9eb0bdf9>] ? _raw_spin_unlock_irq+0x69/0xa0
[ 93.339495] [<ffffffff9eaf95e3>] ? __schedule+0x993/0x1b90
[ 93.339495] [<ffffffff95f49e39>] ? ___preempt_schedule+0x12/0x14
[ 93.339495] [<ffffffff942c4530>] ? abort_exclusive_wait+0x1d0/0x1d0
[ 93.339495] [<ffffffff9433a080>] ? cond_synchronize_rcu+0x20/0x20
[ 93.339495] [<ffffffff94248b56>] kthread+0x216/0x2e0
[ 93.339495] [<ffffffff94248940>] ? flush_kthread_work+0x300/0x300
[ 93.339495] [<ffffffff9eb0bdc0>] ? _raw_spin_unlock_irq+0x30/0xa0
[ 93.339495] [<ffffffff94248940>] ? flush_kthread_work+0x300/0x300
[ 93.339495] [<ffffffff9eb0d293>] ret_from_fork+0x53/0x80
[ 93.339495] [<ffffffff94248940>] ? flush_kthread_work+0x300/0x300

Thanks,
Sasha