Date:	Tue, 15 Sep 2015 20:41:11 +1000
From:	Alexey Kardashevskiy <aik@...abs.ru>
To:	eran ben elisha <eranlinuxmellanox@...il.com>
Cc:	Or Gerlitz <gerlitz.or@...il.com>,
	Eran Ben Elisha <eranbe@...lanox.com>,
	"David S. Miller" <davem@...emloft.net>,
	Jack Morgenstein <jackm@....mellanox.co.il>,
	Matan Barak <matanb@...lanox.com>,
	Or Gerlitz <ogerlitz@...lanox.com>,
	Yishai Hadas <yishaih@...lanox.com>,
	Linux Netdev List <netdev@...r.kernel.org>,
	Richard Yang <weiyang@...ux.vnet.ibm.com>,
	Gavin Shan <gwshan@...ux.vnet.ibm.com>,
	Michael Ellerman <mpe@...erman.id.au>
Subject: Re: [RFC PATCH kernel] Revert "net/mlx4_core: Add port attribute when
 tracking counters"

Any luck with that?


On 09/04/2015 01:36 PM, Alexey Kardashevskiy wrote:
> On 09/03/2015 10:09 PM, eran ben elisha wrote:
>> On Mon, Aug 31, 2015 at 5:39 AM, Alexey Kardashevskiy <aik@...abs.ru> wrote:
>>> On 08/30/2015 04:28 PM, Or Gerlitz wrote:
>>>>
>>>> On Fri, Aug 28, 2015 at 7:06 AM, Alexey Kardashevskiy <aik@...abs.ru>
>>>> wrote:
>>>>>
>>>>> 68230242cdb breaks SRIOV on POWER8 system. I am not really suggesting
>>>>> reverting the patch, rather asking for a fix.
>>>>
>>>>
>>>> thanks for the detailed report, we will look into that.
>>>>
>>>> Just to be sure, when going back in time, what is the latest upstream
>>>> version where
>>>> this system/config works okay? is that 4.1 or later?
>>>
>>>
>>> 4.1 is good, 4.2 is not.
>>>
>>>
>>>
>>>>
>>>>>
>>>>> To reproduce it:
>>>>>
>>>>> 1. boot latest upstream kernel (v4.2-rc8 sha1 4941b8f, ppc64le)
>>>>>
>>>>> 2. Run:
>>>>> sudo rmmod mlx4_en mlx4_ib mlx4_core
>>>>> sudo modprobe mlx4_core num_vfs=4 probe_vf=4 port_type_array=2,2
>>>>> debug_level=1
>>>>>
>>>>> 3. Run QEMU (just to give a complete picture):
>>>>> /home/aik/qemu-system-ppc64 -enable-kvm -m 2048 -machine pseries \
>>>>> -nodefaults \
>>>>> -chardev stdio,id=id0,signal=off,mux=on \
>>>>> -device spapr-vty,id=id1,chardev=id0,reg=0x71000100 \
>>>>> -mon id=id2,chardev=id0,mode=readline -nographic -vga none \
>>>>> -initrd dhclient.cpio -kernel vml400bedbg \
>>>>> -device vfio-pci,id=id3,host=0003:03:00.1
>>>>> What guest is used does not matter at all.
>>>>>
>>>>> 4. Wait till guest boots and then run:
>>>>> dhclient
>>>>> This assigns IPs to both interfaces just fine. This is essential -
>>>>> if interface was not brought up since guest started, the bug does not
>>>>> appear.
>>>>> If interface was up and then down, this still causes the problem
>>>>> (less likely though).
>>>>>
>>>>> 5. Run in the guest: shutdown -h 0
>>>>> Guest prints:
>>>>> mlx4_en: eth0: Close port called
>>>>> mlx4_en: eth1: Close port called
>>>>> mlx4_core 0000:00:00.0: mlx4_shutdown was called
>>>>> And then the host hangs. After 10-30 seconds the host console prints:
>>>>> NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s!
>>>>> [qemu-system-ppc:5095]
>>>>> OR
>>>>> INFO: rcu_sched detected stalls on CPUs/tasks:
>>>>> or some other random stuff but always related to some sort of lockup.
>>>>> Backtraces are like these:
>>>>>
>>>>> [c000001e492a7ac0] [c000000000135b84]
>>>>> smp_call_function_many+0x2f4/0x3fable)
>>>>> [c000001e492a7b40] [c000000000135db8] kick_all_cpus_sync+0x38/0x50
>>>>> [c000001e492a7b60] [c000000000048f38] pmdp_huge_get_and_clear+0x48/0x70
>>>>> [c000001e492a7b90] [c00000000023181c] change_huge_pmd+0xac/0x210
>>>>> [c000001e492a7bf0] [c0000000001fb9e8] change_protection+0x678/0x720
>>>>> [c000001e492a7d00] [c000000000217d38] change_prot_numa+0x28/0xa0
>>>>> [c000001e492a7d30] [c0000000000e0e40] task_numa_work+0x2a0/0x370
>>>>> [c000001e492a7db0] [c0000000000c5fb4] task_work_run+0xe4/0x160
>>>>> [c000001e492a7e00] [c0000000000169a4] do_notify_resume+0x84/0x90
>>>>> [c000001e492a7e30] [c0000000000098b8] ret_from_except_lite+0x64/0x68
>>>>>
>>>>> OR
>>>>>
>>>>> [c000001def1b7280] [c000000ff941d368] 0xc000000ff941d368 (unreliable)
>>>>> [c000001def1b7450] [c00000000001512c] __switch_to+0x1fc/0x350
>>>>> [c000001def1b7490] [c000001def1b74e0] 0xc000001def1b74e0
>>>>> [c000001def1b74e0] [c00000000011a50c] try_to_del_timer_sync+0x5c/0x90
>>>>> [c000001def1b7520] [c00000000011a590] del_timer_sync+0x50/0x70
>>>>> [c000001def1b7550] [c0000000009136fc] schedule_timeout+0x15c/0x2b0
>>>>> [c000001def1b7620] [c000000000910e6c] wait_for_common+0x12c/0x230
>>>>> [c000001def1b7660] [c0000000000fa22c] up+0x4c/0x80
>>>>> [c000001def1b76a0] [d000000016323e60] __mlx4_cmd+0x320/0x940 [mlx4_core]
>>>>> [c000001def1b7760] [c000001def1b77a0] 0xc000001def1b77a0
>>>>> [c000001def1b77f0] [d0000000163528b4] mlx4_2RST_QP_wrapper+0x154/0x1e0
>>>>> [mlx4_core]
>>>>> [c000001def1b7860] [d000000016324934]
>>>>> mlx4_master_process_vhcr+0x1b4/0x6c0 [mlx4_core]
>>>>> [c000001def1b7930] [d000000016324170] __mlx4_cmd+0x630/0x940 [mlx4_core]
>>>>> [c000001def1b79f0] [d000000016346fec]
>>>>> __mlx4_qp_modify.constprop.8+0x1ec/0x350 [mlx4_core]
>>>>> [c000001def1b7ac0] [d000000016292228] mlx4_ib_destroy_qp+0xd8/0x5d0
>>>>> [mlx4_ib]
>>>>> [c000001def1b7b60] [d000000013c7305c] ib_destroy_qp+0x1cc/0x290 [ib_core]
>>>>> [c000001def1b7bb0] [d000000016284548]
>>>>> destroy_pv_resources.isra.14.part.15+0x48/0xf0 [mlx4_ib]
>>>>> [c000001def1b7be0] [d000000016284d28] mlx4_ib_tunnels_update+0x168/0x170
>>>>> [mlx4_ib]
>>>>> [c000001def1b7c20] [d0000000162876e0]
>>>>> mlx4_ib_tunnels_update_work+0x30/0x50 [mlx4_ib]
>>>>> [c000001def1b7c50] [c0000000000c0d34] process_one_work+0x194/0x490
>>>>> [c000001def1b7ce0] [c0000000000c11b0] worker_thread+0x180/0x5a0
>>>>> [c000001def1b7d80] [c0000000000c8a0c] kthread+0x10c/0x130
>>>>> [c000001def1b7e30] [c0000000000095a8] ret_from_kernel_thread+0x5c/0xb4
>>>>>
>>>>> i.e. may or may not mention mlx4.
>>>>> The issue may not happen on a first try but maximum on the second.
>>>>
>>>>
>>>> so when you revert commit 68230242cdb on the host all works just fine?
>>>> what guest driver are you running?
>>>
>>>
>>> To be precise, I did checkout 68230242cdb, checked that it does not work,
>>> then reverted 68230242cdb right there and checked that it works. I did not
>>> try reverting later revisions yet.
>>>
>>> My guest kernel in this test has tag v4.0. I get the same effect with some
>>> 3.18 from Ubuntu 14.04 LTS so the guest kernel version does not make a
>>> difference afaict.
>>>
>>>
>>>> This needs a fix, I don't think the right thing to do is just go and
>>>> revert the commit, if the right fix misses 4.2 we will get it there
>>>> through -stable
>>>
>>>
>>> v4.2 was just released :)
>>>
>>>
>>> --
>>> Alexey
>>
>> Hi Alexey,
>> So far, I failed to reproduce the issue on my setup. However, I found
>> a small error flow bug. can you please try to reproduce with this
>> patch.
>
> Tried, the fix did not change a thing... I cut-n-paste backtrace below.
>
>
>> BTW, are you using CX3/CX3pro or CX2?
>
> CX3pro I believe:
> 0003:03:00.0 Ethernet controller: Mellanox Technologies MT27520 Family
> [ConnectX-3 Pro]
>
>
> aik@...n1:~$ ethtool -i eth4
> driver: mlx4_en
> version: 2.2-1 (Feb 2014)
> firmware-version: 2.34.5000
> bus-info: 0003:03:00.0
> supports-statistics: yes
> supports-test: yes
> supports-eeprom-access: no
> supports-register-dump: no
> supports-priv-flags: yes
>
>
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
>> b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
>> index 731423c..f377550 100644
>> --- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
>> +++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
>> @@ -905,8 +905,10 @@ static int handle_existing_counter(struct
>> mlx4_dev *dev, u8 slave, int port,
>>
>>          spin_lock_irq(mlx4_tlock(dev));
>>          r = find_res(dev, counter_index, RES_COUNTER);
>> -   if (!r || r->owner != slave)
>> -           ret = -EINVAL;
>> + if (!r || r->owner != slave) {
>> +         spin_unlock_irq(mlx4_tlock(dev));
>> +         return -EINVAL;
>> + }
>>          counter = container_of(r, struct res_counter, com);
>>          if (!counter->port)
>>                  counter->port = port;
>>
>
>
> This is how it crashed.
>
> fstn1 login: INFO: rcu_sched self-detected stall on CPU
> INFO: rcu_sched detected stalls on CPUs/tasks:
>          8: (1 GPs behind) idle=4a5/140000000000000/0 softirq=3304/3325
> fqs=133
>          72: (2127 ticks this GP) idle=499/140000000000001/0
> softirq=1634/1634 fq
> s=133
>          (detected by 64, t=2128 jiffies, g=1448, c=1447, q=6160)
> Task dump for CPU 8:
> kworker/u256:1  R  running task    10960   651      2 0x00000804
> Workqueue: mlx4_ibud1 mlx4_ib_tunnels_update_work [mlx4_ib]
> Call Trace:
> [c000001e4d2f32e0] [c00000000006390c] opal_put_chars+0x10c/0x290 (unreliable)
> [c000001e4d2f34b0] [c00000000001512c] __switch_to+0x1fc/0x350
> [c000001e4d2f34f0] [c000001e4d2f3540] 0xc000001e4d2f3540
> [c000001e4d2f3540] [c00000000011a52c] try_to_del_timer_sync+0x5c/0x90
> [c000001e4d2f3580] [c00000000011a5b0] del_timer_sync+0x50/0x70
> [c000001e4d2f35b0] [c00000000091383c] schedule_timeout+0x15c/0x2b0
> [c000001e4d2f3680] [c000000000910fac] wait_for_common+0x12c/0x230
> [c000001e4d2f36c0] [c0000000000fa24c] up+0x4c/0x80
> [c000001e4d2f3700] [d000000016323e60] __mlx4_cmd+0x320/0x940 [mlx4_core]
> [c000001e4d2f37c0] [c000001e4d2f3800] 0xc000001e4d2f3800
> [c000001e4d2f3850] [d00000001634f980] mlx4_HW2SW_MPT_wrapper+0x100/0x180
> [mlx4_c
> ore]
> [c000001e4d2f38c0] [d000000016324934] mlx4_master_process_vhcr+0x1b4/0x6c0
> [mlx4
> _core]
> [c000001e4d2f3990] [d000000016324170] __mlx4_cmd+0x630/0x940 [mlx4_core]
> [c000001e4d2f3a50] [d0000000163409a4] mlx4_HW2SW_MPT.constprop.27+0x44/0x60
> [mlx
> 4_core]
> [c000001e4d2f3ad0] [d00000001634184c] mlx4_mr_free+0xcc/0x110 [mlx4_core]
> [c000001e4d2f3b50] [d0000000162aee2c] mlx4_ib_dereg_mr+0x2c/0x70 [mlx4_ib]
> [c000001e4d2f3b80] [d000000013db12b4] ib_dereg_mr+0x44/0x90 [ib_core]
> [c000001e4d2f3bb0] [d0000000162a4568]
> destroy_pv_resources.isra.14.part.15+0x68/
> 0xf0 [mlx4_ib]
> [c000001e4d2f3be0] [d0000000162a4d28] mlx4_ib_tunnels_update+0x168/0x170
> [mlx4_i
> b]
> [c000001e4d2f3c20] [d0000000162a76e0] mlx4_ib_tunnels_update_work+0x30/0x50
> [mlx
> 4_ib]
> [c000001e4d2f3c50] [c0000000000c0d54] process_one_work+0x194/0x490
> [c000001e4d2f3ce0] [c0000000000c11d0] worker_thread+0x180/0x5a0
> [c000001e4d2f3d80] [c0000000000c8a2c] kthread+0x10c/0x130
> [c000001e4d2f3e30] [c0000000000095a8] ret_from_kernel_thread+0x5c/0xb4
> Task dump for CPU 72:
> qemu-system-ppc R  running task    11248  6389   6289 0x00042004
> Call Trace:
> [c000001e45bf7700] [c000000000e2e990] cpu_online_bits+0x0/0x100 (unreliable)
>
>          72: (2127 ticks this GP) idle=499/140000000000001/0
> softirq=1634/1634 fq
> s=135
>           (t=2128 jiffies g=1448 c=1447 q=6160)
>
>
>
>


-- 
Alexey
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