Re: frequent lockups in 3.18rc4

From: Dave Jones
Date: Thu Nov 20 2014 - 10:25:55 EST

On Wed, Nov 19, 2014 at 01:01:36PM -0800, Andy Lutomirski wrote:

> TIF_NOHZ is not the same thing as NOHZ. Can you try a kernel with
> CONFIG_CONTEXT_TRACKING=n? Doing that may involve fiddling with RCU
> settings a bit. The normal no HZ idle stuff has nothing to do with
> TIF_NOHZ, and you either have TIF_NOHZ set or you have some kind of
> thread_info corruption going on here.

Disabling CONTEXT_TRACKING didn't change the problem.
Unfortunatly the full trace didn't make it over usb-serial this time. Grr.

Here's what came over serial..

NMI watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [trinity-c35:11634]
CPU: 2 PID: 11634 Comm: trinity-c35 Not tainted 3.18.0-rc5+ #94 [loadavg: 164.79 157.30 155.90 37/409 11893]
task: ffff88014e0d96f0 ti: ffff880220eb4000 task.ti: ffff880220eb4000
RIP: 0010:[<ffffffff88379605>] [<ffffffff88379605>] copy_user_enhanced_fast_string+0x5/0x10
RSP: 0018:ffff880220eb7ef0 EFLAGS: 00010283
RAX: ffff880220eb4000 RBX: ffffffff887dac64 RCX: 0000000000006a18
RDX: 000000000000e02f RSI: 00007f766f466620 RDI: ffff88016f6a7617
RBP: ffff880220eb7f78 R08: 8000000000000063 R09: 0000000000000004
R10: 0000000000000010 R11: 0000000000000000 R12: ffffffff880bf50d
R13: 0000000000000001 R14: ffff880220eb4000 R15: 0000000000000001
FS: 00007f766f459740(0000) GS:ffff880244400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f766f461000 CR3: 000000018b00e000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
ffffffff882f4225 ffff880183db5a00 0000000001743440 00007f766f0fb000
fffffffffffffeff 0000000000000000 0000000000008d79 00007f766f45f000
ffffffff8837adae 00ff880220eb7f38 000000003203f1ac 0000000000000001
Call Trace:
[<ffffffff882f4225>] ? SyS_add_key+0xd5/0x240
[<ffffffff8837adae>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff887da092>] system_call_fastpath+0x12/0x17
Code: 48 ff c6 48 ff c7 ff c9 75 f2 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 1f 00 c3 0f 1f 80 00 00 00 00 0f 1f 00 89 d1 <f3> a4 31 c0 0f 1f 00 c3 90 90 90 0f 1f 00 83 fa 08 0f 82 95 00
sending NMI to other CPUs:

Here's a crappy phonecam pic of the screen.
There's a bit of trace missing between the above and what was on
the screen, so we missed some CPUs.


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