Date:   Fri, 15 Mar 2019 21:46:39 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Alexander Duyck <alexander.h.duyck@...ux.intel.com>,
        VDR User <user.vdr@...il.com>
Cc:     netdev@...r.kernel.org
Subject: Re: r8169 driver from kernel 5.0 crashing - napi_consume_skb

On 15.03.2019 21:40, Alexander Duyck wrote:
> On Fri, 2019-03-15 at 21:26 +0100, Heiner Kallweit wrote:
>> On 15.03.2019 21:09, VDR User wrote:
>>>>>>> Thanks for the additional info and for testing 4.20.15.
>>>>>>> To rule out that the issue is caused by a regression in network or
>>>>>>> some other subsystem: Can you take the r8169.c from 4.20.15 and test
>>>>>>> it on top of 5.0?
>>>>>>> Meanwhile I'll look at the changes in the driver between 4.20 and 5.0.
>>>>>>
>>>>>> Sure, no problem! I'll copy the driver & recompile now actually.
>>>>>> Hopefully there aren't a ton of changes to r8169.c to sift through and
>>>>>> the cause isn't good at hiding itself!
>>>>>>
>>>>> I checked the driver changes new in 5.0 and there are very few
>>>>> functional changes. You could try to revert the following:
>>>>>
>>>>> 5317d5c6d47e ("r8169: use napi_consume_skb where possible")
>>>>
>>>> Will do, and fwiw, while I haven't been able to do tons of testing
>>>> today, I haven't been able to trigger the crash after replacing
>>>> 5.0.0's r8169.c with 4.20.15's r8169.c this morning. I'll restore the
>>>> file and revert the change you mentioned, and report back my findings.
>>>
>>> Heiner,
>>>
>>> After going back to vanilla kernel 5.0 and then reverting 5317d5c6d47e
>>> ("r8169: use napi_consume_skb where possible"), I so far have not had
>>> any crashes after transferring roughly 30GB back & forth. I'm not
>>> completely confident yet the crash is resolve with that revert and
>>> will continue to do further testing throughout the weekend as well.
>>> What confidence level do you have that 5317d5c6d47e is the culprit at
>>> this point?
>>>
>> Good, thanks for testing. I simply see no other change since 4.20 that
>> could cause these symptoms.
>> Using napi_consume_skb() at this place in r8169.c looks safe to me.
>> Option 1 is that I miss something, option 2 is that there's an issue
>> in the NAPI subsystem. However in the latter case I assume at least
>> the Mellanox and/or Intel guys would have observed the same issue
>> on their respective CI systems.
>> Let me add Alexander, maybe he can provide a hint before we go and
>> revert the change.
> 
> Do you have the crash log? I'd be curious what the issue is we are
> seeing.
> 
> I agree I can't see anything obvious, but it is possible that we may be
> running into something we hadn't seen with the Intel and Mellanox
> parts.
> 
> - Alex
> 
> 
Crash may have been the wrong word, network becomes unresponsive
and the user sees the generic transmit queue timeout.
Let me quote his original mail:

------------------------------------------------------------------------

Hi, after updating to kernel 5.0, the nic driver (r8169) has been
crashing whenever I start using heavy traffic on it (for example,
xferring large files to the box across my lan). The destination
harddrive may be sleeping and need to spin-up, or not, but the box
itself does not suspend/hibernate. The nic becomes completely
unresponsive and all connections to the box drop. After what I think
is several minutes, the connection comes back to life. The problem
happens consistently but seemingly not consistently at the same point.
For example, I can xfer a few 4gb files and it will crash at around
2-3gb on the first file. The next time it might not crash until 2-3gb
on the second file.Prior to kernel 5.0 I was using 4.19.12 and this
problem didn't occur. I have since downgraded back to 4.19.12 pending
what response this post gets.

Thanks for any help or assistance on how to proceed!
-Derek

NOTE: I'm not subscribed to this mailing list so please CC me on any replies!

The nic is on-board ECS A75F-A:
04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)
        Subsystem: Elitegroup Computer Systems RTL8111/8168/8411 PCI
Express Gigabit Ethernet Controller
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 17
        Region 0: I/O ports at c000 [size=256]
        Region 2: Memory at d0004000 (64-bit, prefetchable) [size=4K]
        Region 4: Memory at d0000000 (64-bit, prefetchable) [size=16K]
        Capabilities: <access denied>
        Kernel driver in use: r8169

I see the following in the syslog:

[164572.785517] ------------[ cut here ]------------
[164572.785595] NETDEV WATCHDOG: enp4s0 (r8169): transmit queue 0 timed out
[164572.785677] WARNING: CPU: 1 PID: 0 at net/sched/sch_generic.c:461
dev_watchdog+0x1bb/0x1e0
[164572.785730] Modules linked in: snd_hda_codec_realtek
snd_hda_codec_generic snd_hda_codec_hdmi ohci_pci snd_hda_intel
snd_hda_codec snd_hwdep xhci_pci ehci_pci ohci_hcd xhci_hcd ehci_hcd
usbcore usb_common snd_hda_core snd_pcm snd_timer snd soundcore nfsd
auth_rpcgss oid_registry lockd grace sunrpc ip_tables x_tables ipv6
[164572.785807] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.0.0-amd #2
[164572.785842] Hardware name: ECS A75F-A/A75F-A, BIOS 4.6.5 09/14/2011
[164572.785878] EIP: dev_watchdog+0x1bb/0x1e0
[164572.785912] Code: 8b 50 3c 89 f8 e8 3d aa 0a 00 8b 7e f4 eb a4 89
f8 c6 05 e7 1c 6d c1 01 e8 72 4f fd ff 53 50 57 68 78 05 66 c1 e8 25
ad ba ff <0f> 0b 83 c4 10 eb c9 eb 1c 8d b4 26 00 00 00 00 8d b4 26 00
00 00
[164572.785963] EAX: 0000003b EBX: 00000000 ECX: 00000800 EDX: 00000103
[164572.785998] ESI: f4cbc264 EDI: f4cbc000 EBP: f4c99f74 ESP: f4c99f4c
[164572.786033] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210296
[164572.786067] CR0: 80050033 CR2: 020dc000 CR3: 2b80b000 CR4: 00000690
[164572.786102] Call Trace:
[164572.786135]  <SOFTIRQ>
[164572.786168]  ? qdisc_put_unlocked+0x40/0x40
[164572.786203]  call_timer_fn+0x19/0xa0
[164572.786237]  run_timer_softirq+0x337/0x380
[164572.786270]  ? qdisc_put_unlocked+0x40/0x40
[164572.786302]  ? rcu_process_callbacks+0xcb/0x380
[164572.786337]  __do_softirq+0xd6/0x21c
[164572.786370]  ? __irqentry_text_end+0x18/0x18
[164572.786404]  call_on_stack+0x10/0x60
[164572.786435]  </SOFTIRQ>
[164572.786467]  ? irq_exit+0x91/0xc0
[164572.786495]  ? smp_apic_timer_interrupt+0x56/0xa0
[164572.786525]  ? apic_timer_interrupt+0xd5/0xdc
[164572.786555]  ? acpi_idle_enter_s2idle+0x60/0x60
[164572.786584]  ? cpuidle_enter_state+0x122/0x360
[164572.786614]  ? tick_nohz_idle_stop_tick+0x27b/0x2a0
[164572.786644]  ? cpuidle_enter+0xf/0x20
[164572.786673]  ? call_cpuidle+0x1c/0x40
[164572.786701]  ? do_idle+0x1e6/0x220
[164572.786730]  ? cpu_startup_entry+0x25/0x40
[164572.786758]  ? start_secondary+0x1a5/0x220
[164572.786787]  ? startup_32_smp+0x15f/0x164
[164572.786816] ---[ end trace 662a5195537dbad8 ]---

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