On 09/03/2015 10:09 PM, eran ben elisha wrote:

On Mon, Aug 31, 2015 at 5:39 AM, Alexey Kardashevskiy [off-list ref] wrote:

quoted

On 08/30/2015 04:28 PM, Or Gerlitz wrote:

quoted

On Fri, Aug 28, 2015 at 7:06 AM, Alexey Kardashevskiy [off-list ref]
wrote:

quoted

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.

quoted

quoted

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.

quoted

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@fstn1:~$ 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

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