Well, yes I agree, it does look like the serial port causing the softlockup is probably separate - but caused by - the nbd closed socket errors. However, the serial port output definitely shouldn't be causing a softlockup - no matter how much data it has to send, the serial port driver in the kernel should be scheduling itself during operation, so that it doesn't hog a single cpu for a long time. It's more likely that the general system "freezing" you are seeing is due to the serial port driver refusing to schedule off its cpu, and not any problem with the nbdX failure.
I'll look into the nbd code also though, to see where that error is coming from and what that problem may be. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1505564 Title: Soft lockup with "block nbdX: Attempted send on closed socket" spam Status in linux package in Ubuntu: In Progress Bug description: Some of our nova compute hosts regularly freeze, sometimes for a few hours, with kern.log getting spammed with: block nbdX: Attempted send on closed socket and a few "CPU soft lockup" messages (see attached log). This clears up when the queue gets cleared, eg : block nbdX: queue cleared trusty hosts with kernel version 3.19.0-30-generic. --- AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Nov 24 12:23 seq crw-rw---- 1 root audio 116, 33 Nov 24 12:23 timer AplayDevices: Error: [Errno 2] No such file or directory ApportVersion: 2.14.1-0ubuntu3.19 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: DistroRelease: Ubuntu 14.04 IwConfig: Error: [Errno 2] No such file or directory MachineType: HP ProLiant DL385 G7 Package: linux (not installed) PciMultimedia: ProcEnviron: TERM=screen-256color PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 radeondrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-36-generic root=UUID=13289ac9-8dc9-4feb-b6bd-ca7db66b21d6 ro console=tty0 console=ttyS1,38400 nosplash crashkernel=384M-:512M nox2apic intremap=off ProcVersionSignature: Ubuntu 3.19.0-36.41~14.04.1hf00090138v20151122b1-generic 3.19.8-ckt9 RelatedPackageVersions: linux-restricted-modules-3.19.0-36-generic N/A linux-backports-modules-3.19.0-36-generic N/A linux-firmware 1.127.18 RfKill: Error: [Errno 2] No such file or directory Tags: trusty uec-images Uname: Linux 3.19.0-36-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: _MarkForUpload: True dmi.bios.date: 02/02/2014 dmi.bios.vendor: HP dmi.bios.version: A18 dmi.chassis.type: 23 dmi.chassis.vendor: HP dmi.modalias: dmi:bvnHP:bvrA18:bd02/02/2014:svnHP:pnProLiantDL385G7:pvr:cvnHP:ct23:cvr: dmi.product.name: ProLiant DL385 G7 dmi.sys.vendor: HP To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1505564/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
