Bug 212573 - netconsole triggers warning in netpoll_poll_dev
Summary: netconsole triggers warning in netpoll_poll_dev
Status: NEW
Alias: None
Product: Networking
Classification: Unclassified
Component: Other (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Stephen Hemminger
Depends on:
Reported: 2021-04-06 08:17 UTC by Oleksandr Natalenko
Modified: 2021-05-08 10:27 UTC (History)
1 user (show)

See Also:
Kernel Version: 5.12.2
Tree: Mainline
Regression: No

Fix from Jesse Brandeburg of Intel (2.24 KB, patch)
2021-05-07 06:33 UTC, Oleksandr Natalenko
Details | Diff

Description Oleksandr Natalenko 2021-04-06 08:17:46 UTC

I'm experiencing the following woes while using netconsole regularly:

[22038.710800] ------------[ cut here ]------------
[22038.710801] igb_poll+0x0/0x1440 [igb] exceeded budget in poll
[22038.710802] WARNING: CPU: 12 PID: 40362 at net/core/netpoll.c:155 netpoll_poll_dev+0x18a/0x1a0
[22038.710802] Modules linked in: blocklayoutdriver rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc nfs_ssc fscache uinput netconsole rfcomm nft_ct nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 cmac algif_hash algif_skcipher af_alg nf_tables tun bnep nfnetlink iwlmvm snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio mac80211 snd_hda_codec_hdmi snd_hda_intel nls_iso8859_1 snd_intel_dspcfg soundwire_intel vfat libarc4 soundwire_generic_allocation soundwire_cadence fat intel_rapl_msr snd_hda_codec intel_rapl_common iwlwifi snd_hda_core soundwire_bus snd_usb_audio snd_soc_core eeepc_wmi btusb asus_wmi snd_usbmidi_lib btrtl edac_mce_amd sparse_keymap btbcm video wmi_bmof mxm_wmi kvm_amd snd_hwdep snd_compress btintel snd_rawmidi ac97_bus cfg80211 uvcvideo bluetooth snd_pcm_dmaengine snd_seq_device snd_pcm videobuf2_vmalloc kvm videobuf2_memops snd_timer videobuf2_v4l2 joydev igb mousedev ecdh_generic snd irqbypass pl2303 ipmi_devintf ecc videobuf2_common soundcore
[22038.710820]  r8169 ipmi_msghandler rapl crc16 k10temp rfkill sp5100_tco dca i2c_piix4 tpm_crb realtek mdio_devres tpm_tis libphy tpm_tis_core pinctrl_amd wmi acpi_cpufreq mac_hid tcp_bbr2 vhost_vsock vmw_vsock_virtio_transport_common vhost vhost_iotlb vsock v4l2loopback videodev mc nct6775 hwmon_vid crypto_user fuse ip_tables x_tables xfs dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c crc32c_generic dm_crypt cbc encrypted_keys trusted tpm hid_logitech_hidpp hid_logitech_dj usbhid dm_mod raid10 crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel md_mod crypto_simd cryptd glue_helper ccp amdgpu rng_core xhci_pci xhci_pci_renesas drm_ttm_helper ttm gpu_sched i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops cec drm agpgart
[22038.710835] CPU: 12 PID: 40362 Comm: systemd-sleep Not tainted 5.11.0-pf7 #1
[22038.710836] Hardware name: ASUS System Product Name/Pro WS X570-ACE, BIOS 3302 03/05/2021
[22038.710836] RIP: 0010:netpoll_poll_dev+0x18a/0x1a0
[22038.710837] Code: 6e ff 80 3d d2 9d f8 00 00 0f 85 5c ff ff ff 48 8b 73 28 48 c7 c7 0c b8 21 84 89 44 24 04 c6 05 b6 9d f8 00 01 e8 84 21 1c 00 <0f> 0b 8b 54 24 04 e9 36 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00
[22038.710838] RSP: 0018:ffffb24106e37ba0 EFLAGS: 00010086
[22038.710838] RAX: 0000000000000000 RBX: ffff9599d2929c50 RCX: ffff959f8ed1ac30
[22038.710839] RDX: 0000000000000000 RSI: 0000000000000023 RDI: ffff959f8ed1ac28
[22038.710839] RBP: ffff9598981d4058 R08: 0000000000000019 R09: ffffb24206e3796d
[22038.710839] R10: ffffffffffffffff R11: ffffb24106e37968 R12: ffff959887e51ec8
[22038.710840] R13: 000000000000000c R14: 00000000ffffffff R15: ffff9599d2929c60
[22038.710840] FS:  00007f3ade370a40(0000) GS:ffff959f8ed00000(0000) knlGS:0000000000000000
[22038.710841] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[22038.710841] CR2: 0000000000000000 CR3: 00000003017b0000 CR4: 0000000000350ee0
[22038.710841] Call Trace:
[22038.710842]  netpoll_send_skb+0x185/0x240
[22038.710842]  write_msg+0xe5/0x100 [netconsole]
[22038.710842]  console_unlock+0x37d/0x640
[22038.710842]  ? __schedule+0x2e5/0xc90
[22038.710843]  suspend_devices_and_enter+0x2ac/0x7f0
[22038.710843]  pm_suspend.cold+0x321/0x36c
[22038.710843]  state_store+0xa6/0x140
[22038.710844]  kernfs_fop_write_iter+0x124/0x1b0
[22038.710844]  new_sync_write+0x16a/0x200
[22038.710844]  vfs_write+0x21c/0x2e0
[22038.710844]  __x64_sys_write+0x6d/0xf0
[22038.710845]  do_syscall_64+0x33/0x40
[22038.710845]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[22038.710845] RIP: 0033:0x7f3adece10f7
[22038.710846] Code: 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[22038.710847] RSP: 002b:00007ffc51c555b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[22038.710847] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f3adece10f7
[22038.710848] RDX: 0000000000000004 RSI: 00007ffc51c556a0 RDI: 0000000000000004
[22038.710848] RBP: 00007ffc51c556a0 R08: 000055ea374302a0 R09: 00007f3aded770c0
[22038.710849] R10: 00007f3aded76fc0 R11: 0000000000000246 R12: 0000000000000004
[22038.710849] R13: 000055ea3742c430 R14: 0000000000000004 R15: 00007f3adedb3700
[22038.710849] ---[ end trace 6eae54fbf23807f8 ]---

This one happened during suspend/resume cycle (on resume), followed by:

[22038.868669] igb 0000:05:00.0 enp5s0: Reset adapter
[22040.998673] igb 0000:05:00.0 enp5s0: Reset adapter
[22043.819198] igb 0000:05:00.0 enp5s0: igb: enp5s0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX

I've bumped into a similar issue in BZ 211911 (see c#16), and in c#17 it was suggested it was a separate unrelated issue, hence I'm creating a new BZ.

Please help in finding out why this woe happens and in fixing it.

Comment 1 Willem de Bruijn 2021-04-06 12:29:31 UTC
[22038.710801] igb_poll+0x0/0x1440 [igb] exceeded budget in poll
[22038.710802] WARNING: CPU: 12 PID: 40362 at net/core/netpoll.c:155 

        WARN_ONCE(work, "%pS exceeded budget in poll\n", napi->poll);

Sounds like a driver issue. You may want to bring this up on the intel-wired-lan list.
Comment 2 Oleksandr Natalenko 2021-04-06 12:42:11 UTC
Thanks for the suggestion, posted an email here: [1]

[1] https://lore.kernel.org/lkml/20210406123619.rhvtr73xwwlbu2ll@spock.localdomain/
Comment 3 Stephen Hemminger 2021-04-06 15:09:51 UTC
The logic in igb_poll() is going to do a receive of one packet even when called with a budget of zero.

It is a off by one in the logic of igb_clean_rx_irq() here:
	while (likely(total_packets < budget)) {
Comment 4 Kris Karas 2021-04-06 21:20:43 UTC
I have seen this regularly for a long time now.
It is not specific to suspend/resume.

The stack trace I see is largely the same as of the OP, but with the addition of  bridge devices.  On every boot, the system goes to perform a CIFS mount of \\Server\Share, and triggers this:
    igb_poll+0x0/0x1290 exceeded budget in poll
    cifs_smb3_do_mount.cold+0x2f/0x60 [cifs]

And of course, the outgoing packet is never sent over the wire.
Only one such WARN is printed per system uptime.
Comment 5 Oleksandr Natalenko 2021-04-06 21:23:54 UTC

it seems the issue pops up for you more often than it does for me. Would it be possible for you to verify suggested patch [1]?


[1] https://lore.kernel.org/lkml/20210406114734.0e00cb2f@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/
Comment 6 Kris Karas 2021-04-06 21:31:01 UTC
Incidentally – and this comment is /off topic/ but included for completeness – these netconsole events have not been logged to the syslog server I have in a long time.

It seems that the sysklogd package (from Debian/Ubuntu/NetBSD/FreeBSD) has recently started adhering more closely to RFC3164 and RFC5424, one side-effect being that improperly formatted syslog UDP packages on port 514 are discarded.  And netconsole has been improperly formatting packets for quite some time, specifically in omitting the "<PRI>" string required at the start of each submission.  Curiously, <PRI> is included and is parsed by "dmesg" to colorize output (etc), but gets stripped (or not generated?) when going via netconsole.
Comment 7 Kris Karas 2021-04-06 21:32:30 UTC
I will give the patch in comment #5 a whirl when I get a free moment here...
Comment 8 Kris Karas 2021-04-07 01:06:14 UTC
I just tested the patch in comment #5 and am running it as I pen this.  Alas, it made no difference.  The warning and stack trace appear identical.

P.S.  A correction: I stated incorrectly in comment #4 that packets were not being pushed out by netconsole with the igb driver.  They are indeed sent, and I am (with a patched syslogd to work around the issue in comment #6) receiving them on the syslog server.
Comment 9 Oleksandr Natalenko 2021-05-07 06:33:56 UTC
Created attachment 296685 [details]
Fix from Jesse Brandeburg of Intel
Comment 10 Oleksandr Natalenko 2021-05-07 06:34:39 UTC

would it be possible for you to test the patch I've just attached?

Comment 11 Kris Karas 2021-05-07 07:23:48 UTC
I was hoping that the new patch might work, but, alas, no joy.
Applying the fix from Jesse Brandenburg results in no visible changes, same stack trace as before.  (This was tested against mainline 5.12.1)
Comment 12 Oleksandr Natalenko 2021-05-08 10:27:59 UTC
OK, it does not work for me as well. I've just given a feedback on this patch to the developer.


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