Re: rhashtable: hang while running tests on boot

[Sasha Levin]

On 10/11/2014 11:52 AM, Paul E. McKenney wrote:
> On Sat, Oct 11, 2014 at 08:41:26AM -0400, Sasha Levin wrote:
>> > On 10/10/2014 10:22 AM, Paul E. McKenney wrote:
>>> > > I am guessing that this happens only when running the resizable hashtable
>>> > > tests -- if that guess is incorrect, please let me know.
>> > 
>> > Paul, I'm not sure if it's related or not - but I'm also seeing quite a few
>> > unexplainable (read: which I can't explain) RCU stalls:
>> > 
>> > [ 2121.852211] INFO: rcu_preempt detected stalls on CPUs/tasks:
>> > [ 2121.852233]  0: (244 ticks this GP) idle=1f7/140000000000002/0 softirq=18045/18045 last_accelerate: 7794/c7aa, nonlazy_posted: 576737, ..
>> > [ 2121.852260]  (detected by 7, t=20502 jiffies, g=16439, c=16438, q=63119)
>> > [ 2121.852265] Task dump for CPU 0:
>> > [ 2121.852294] ksoftirqd/0     R  running task    13504     3      2 0x10080008
>> > [ 2121.852307]  ffff880068203d88 ffffffff8efe9a34 ffff880068203d48 0000000000000000
>> > [ 2121.852317]  ffff8800681c3000 ffff880068200010 ffff880068200000 000001bae312d5a9
>> > [ 2121.852327]  ffff880064a5b000 ffff880064a5b000 ffff880068203d78 0000000000000000
>> > [ 2121.852330] Call Trace:
>> > [ 2121.852354]  [<ffffffff8efe9a34>] ? __schedule+0x614/0xdd0
>> > [ 2121.852364]  [<ffffffff8efea230>] schedule+0x40/0xb0
>> > [ 2121.852378]  [<ffffffff8a1fe4a8>] smpboot_thread_fn+0x1b8/0x420
>> > [ 2121.852389]  [<ffffffff8a1c7a90>] ? tasklet_init+0x70/0x70
>> > [ 2121.852399]  [<ffffffff8a1fe2f0>] ? SyS_setgroups+0x1e0/0x1e0
>> > [ 2121.852410]  [<ffffffff8a1f7aa4>] kthread+0x144/0x170
>> > [ 2121.852420]  [<ffffffff8efec2cf>] ? wait_for_completion+0x10f/0x160
>> > [ 2121.852431]  [<ffffffff8a1f7960>] ? flush_kthread_work+0x1d0/0x1d0
>> > [ 2121.852440]  [<ffffffff8eff4a3c>] ret_from_fork+0x7c/0xb0
>> > [ 2121.852450]  [<ffffffff8a1f7960>] ? flush_kthread_work+0x1d0/0x1d0
> Does the following patch help?  (If you kernel does not have a
> rcu_note_voluntary_context_switch(), replace this with
> rcu_note_context_switch().)

That patch was already in my tree (-next).


Thanks,
Sasha
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