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Date:   Thu, 24 Oct 2019 13:41:34 -0700
From:   Davidlohr Bueso <dave@stgolabs.net>
To:     Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: WARNING: at net/sched/sch_generic.c:448
Message-ID: <20191024204134.egc5mdtz2o2tsxyz@linux-p48b>
References: <20191024032105.xmewznsphltnrido@linux-p48b>
 <87mudpylcc.fsf@linux.intel.com>
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On Thu, 24 Oct 2019, Vinicius Costa Gomes wrote:

>Hi,
>
>Davidlohr Bueso <dave@stgolabs.net> writes:
>
>> Hi,
>>
>> I'm hitting the following in linux-next, and as far back as v5.2, ring any bells?
>>
>> [  478.588144] NETDEV WATCHDOG: eth0 (igb): transmit queue 0 timed out
>> [  478.601994] WARNING: CPU: 10 PID: 74 at net/sched/sch_generic.c:448 dev_watchdog+0x253/0x260
>> [  478.620613] Modules linked in: ebtable_filter(E) ebtables(E) ip6table_filter(E) ip6_tables(E) iptable_filter(E) ip_tables(E) x_tables(E) bpfilter(E) scsi_transport_iscsi(E) af_packet(E) iscsi_ibft(E) iscsi_boot_sysfs(E) ext4(E) intel_rapl_msr(E) intel_rapl_common(E) crc16(E) mbcache(E) jbd2(E) sb_edac(E) x86_pkg_temp_thermal(E) intel_powerclamp(E) coretemp(E) kvm_intel(E) kvm(E) irqbypass(E) crc32_pclmul(E) iTCO_wdt(E) ghash_clmulni_intel(E) iTCO_vendor_support(E) aesni_intel(E) crypto_simd(E) cryptd(E) glue_helper(E) ipmi_si(E) igb(E) ioatdma(E) pcspkr(E) ipmi_devintf(E) mei_me(E) lpc_ich(E) mfd_core(E) ipmi_msghandler(E) joydev(E) i2c_i801(E) mei(E) dca(E) button(E) btrfs(E) libcrc32c(E) xor(E) raid6_pq(E) hid_generic(E) usbhid(E) sd_mod(E) mgag200(E) drm_kms_helper(E) syscopyarea(E) sysfillrect(E) sysimgblt(E) fb_sys_fops(E) i2c_algo_bit(E) isci(E) ehci_pci(E) drm_vram_helper(E) ahci(E) ehci_hcd(E) libsas(E) crc32c_intel(E) ttm(E) libahci(E) scsi_transport_sas(E) drm(E) usbcore(E)
>> [  478.620658]  libata(E) wmi(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E)
>> [  478.837008] CPU: 10 PID: 74 Comm: ksoftirqd/10 Kdump: loaded Tainted: G            E     5.4.0-rc4-2-default+ #2
>> [  478.859457] Hardware name: Intel Corporation LH Pass/SVRBD-ROW_P, BIOS SE5C600.86B.02.01.SP04.112220131546 11/22/2013
>> [  478.882867] RIP: 0010:dev_watchdog+0x253/0x260
>
>Not ringing any bells, but if this timeout is happening, you should also
>be seeing some igb "TX Hang" warnings. Usually this warning happens when
>some packet is stuck (for whatever reason) in the transmission queue.

I am not seeing any TX hang warnings, only the workqueue lockup message
(igb_watchdog_task).

>
>Can you share more details about what you are running? specially the
>kind of configuration (if any) you are doing to the controller.

I am able to trigger this a few seconds into running pi_stress (from
rt-tests, quite a non network workload). But this is not the only one.
I'm going through some logs to see what other test is triggering it.

Also, no tweaking whatsoever to the controller.

Thanks,
Davidlohr