apport information ** Attachment added: "CurrentDmesg.txt" https://bugs.launchpad.net/bugs/1349768/+attachment/4165025/+files/CurrentDmesg.txt
-- 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/1349768 Title: kernel 3.13.0-32 ipvs "IPv6 header not found" related to UDP socket sendto() EPERM errors Status in “linux” package in Ubuntu: Confirmed Bug description: I have an Ubuntu 14.04 host that I am using as both a keepalived/ipvs loadbalancer and dnsmasq server for pxebooting servers. After updating linux-image 3.13.0-29.53 -> 3.13.0-32.57 I noticed that dnsmasq-tftp stopped working. pxeboot clients would hang on the "Loading ..../linux" TFTP transfer, with the transfer stalling roughly ~1000 blocks into the transfer: 10:30:51.011728 IP 10.1.1.2.43540 > 10.1.12.1.49165: UDP, length 1412 10:30:51.011924 IP 10.1.12.1.49165 > 10.1.1.2.43540: UDP, length 4 10:30:51.012012 IP 10.1.1.2.43540 > 10.1.12.1.49165: UDP, length 1412 10:30:51.012183 IP 10.1.12.1.49165 > 10.1.1.2.43540: UDP, length 4 stracing dnsmasq I noticed something very odd: sendto() on the socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) would suddenly start persistently returning EPERM in mid-transfer, even when dnsmasq continued to periodically retry: select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 1 (in [17], left {0, 249834}) recvfrom(17, "\0\4\3\352", 4096, 0, NULL, NULL) = 4 lseek(16, 1410816, SEEK_SET) = 1410816 read(16, "\25\306\345f\2{\r\4)W\276\32\336q\252_\230q\213\341U\354\25\374k7\243\32\221X+\v"..., 1408) = 1408 sendto(17, "\0\3\3\353\25\306\345f\2{\r\4)W\276\32\336q\252_\230q\213\341U\354\25\374k7\243\32"..., 1412, 0, {sa_family=AF_INET, sin_port=htons(49165), sin_addr=inet_addr("10.1.11.3")}, 16) = 1412 select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 1 (in [17], left {0, 249839}) recvfrom(17, "\0\4\3\353", 4096, 0, NULL, NULL) = 4 lseek(16, 1412224, SEEK_SET) = 1412224 read(16, "*\360 <C\363l\320:\256~\307\236\26P\323\274%\260\362\341&\232\r\243\370\224\277\221\\\307\372"..., 1408) = 1408 sendto(17, "\0\3\3\354*\360 <C\363l\320:\256~\307\236\26P\323\274%\260\362\341&\232\r\243\370\224\277"..., 1412, 0, {sa_family=AF_INET, sin_port=htons(49165), sin_addr=inet_addr("10.1.11.3")}, 16) = -1 EPERM (Operation not permitted) select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 0 (Timeout) select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 0 (Timeout) select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 0 (Timeout) select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 0 (Timeout) select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 0 (Timeout) select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 0 (Timeout) select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 0 (Timeout) select(18, [4 5 6 7 8 9 10 11 12 15 17], [], [], {0, 250000}) = 0 (Timeout) lseek(16, 1412224, SEEK_SET) = 1412224 read(16, "*\360 <C\363l\320:\256~\307\236\26P\323\274%\260\362\341&\232\r\243\370\224\277\221\\\307\372"..., 1408) = 1408 sendto(17, "\0\3\3\354*\360 <C\363l\320:\256~\307\236\26P\323\274%\260\362\341&\232\r\243\370\224\277"..., 1412, 0, {sa_family=AF_INET, sin_port=htons(49165), sin_addr=inet_addr("10.1.11.3")}, 16) = -1 EPERM (Operation not permitted) This was with all iptables rules unloaded (so no OUTPUT -j DENY) and apparmor profiles torn down. I also noticed the following dmesgs appearing at roughly similar times to the tftp transfers getting stuck (although not coinciding exactly with the stall): [70325.516724] IPv6 header not found The error pointed to ipvs (which I am using on the same host as an IPv4 NAT loadbalancer): http://archive.linuxvirtualserver.org/html/lvs-devel/2012-08/msg00018.html http://comments.gmane.org/gmane.comp.linux.lvs.devel/3614 I then tore down the ipvs rules (service keepalived stop) and unloaded the modules (rmmod ip_vs_rr ip_vs), and the issue resolved itself - the stalled dnsmasq-tftp transfer resumed! This seems to be reproducible, i.e. modprobing ip_vs and starting keepalived will cause dnsmasq-tftp to stall again, and stopping/unloading will resume. This seems to happen reproducibly on boot with -32 and -30. This does NOT seem to happen with 3.13.0-29 which I was using up until now. --- AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Jul 29 13:43 seq crw-rw---- 1 root audio 116, 33 Jul 29 13:43 timer AplayDevices: Error: [Errno 2] No such file or directory ApportVersion: 2.14.1-0ubuntu3.2 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: CRDA: Error: [Errno 2] No such file or directory DistroRelease: Ubuntu 14.04 HibernationDevice: RESUME=/dev/mapper/catcp2-swap InstallationDate: Installed on 2014-06-03 (56 days ago) InstallationMedia: Ubuntu-Server 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.2) MachineType: Dell Inc. PowerEdge R410 Package: linux-image-3.13.0-32-generic 3.13.0-32.57 PackageArchitecture: amd64 PciMultimedia: ProcEnviron: TERM=xterm PATH=(custom, no user) LANG=C.UTF-8 SHELL=/bin/bash ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.13.0-32-generic root=/dev/mapper/hostname-root ro console=ttyS1,115200n8 console=tty0 nomdmonddf nomdmonisw ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4 RelatedPackageVersions: linux-restricted-modules-3.13.0-32-generic N/A linux-backports-modules-3.13.0-32-generic N/A linux-firmware 1.127.5 RfKill: Error: [Errno 2] No such file or directory Tags: trusty Uname: Linux 3.13.0-32-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: _MarkForUpload: True dmi.bios.date: 07/30/2013 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.12.0 dmi.board.name: 01V648 dmi.board.vendor: Dell Inc. dmi.board.version: A03 dmi.chassis.type: 23 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr1.12.0:bd07/30/2013:svnDellInc.:pnPowerEdgeR410:pvr:rvnDellInc.:rn01V648:rvrA03:cvnDellInc.:ct23:cvr: dmi.product.name: PowerEdge R410 dmi.sys.vendor: Dell Inc. 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