I have tested this on kernel 4.4.0 (in Xenial) and I don't think the fix that went into 3.19 fixed the entire issue.
My understanding is that since nmap uses a relatively long pcap_select() timeout, and the packet buffers in the kernel aren't filling up fast enough, the packet loss can still be seen. I see that you have worked around this in nmap by disabling TPACKET_v3: https://github.com/nmap/nmap/commit/83b9c4c939094e673705b7c270533708853891f0 I noticed that another project (which I found linked to the libpcap bug) worked around this issue by using libpcap's immediate_mode: https://github.com/teclo/flow- disruptor/commit/3376d049fc5280aedccc42fc6e090c32c0c4a128 Would you consider trying this same workaround in nmap, since it seems more general than forcing TPACKET_V3 to be disabled? (That is, only users who compile nmap from source and use "./configure --with- libpcap=included" can currently use the workaround.) ** Bug watch added: github.com/nmap/nmap/issues #34 https://github.com/nmap/nmap/issues/34 ** Also affects: linux via https://github.com/nmap/nmap/issues/34 Importance: Unknown Status: Unknown ** Project changed: linux => nmap ** Bug watch added: github.com/the-tcpdump-group/libpcap/issues #380 https://github.com/the-tcpdump-group/libpcap/issues/380 ** Also affects: tcpdump via https://github.com/the-tcpdump-group/libpcap/issues/380 Importance: Unknown Status: Unknown -- 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/1457472 Title: TPACKET_V3 in Linux before 3.19 causes packet loss in libpcap Status in nmap: Unknown Status in tcpdump: Unknown Status in linux package in Ubuntu: Triaged Bug description: Observed packet loss and major slowdown in Nmap on Ubuntu 14.04: https://github.com/nmap/nmap/issues/34 Traced to this bug report for libpcap 1.5.3: https://github.com/the- tcpdump-group/libpcap/issues/380 Underlying issue is a bug in the Linux kernel which was fixed in 3.19: https://github.com/torvalds/linux/commit/da413ee Please backport this patch to Ubuntu 14.04 LTS kernel. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.13.0-53-generic 3.13.0-53.89 ProcVersionSignature: Ubuntu 3.13.0-53.89-generic 3.13.11-ckt19 Uname: Linux 3.13.0-53-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.10 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: nmap 12401 F.... pulseaudio /dev/snd/pcmC0D0c: nmap 12401 F...m pulseaudio /dev/snd/pcmC0D0p: nmap 12401 F...m pulseaudio /dev/snd/timer: nmap 12401 f.... pulseaudio CurrentDmesg: [ 25.541696] init: plymouth-upstart-bridge main process ended, respawning Date: Thu May 21 07:42:08 2015 HibernationDevice: RESUME=UUID=e4b6770e-dcc5-445d-a445-25d9a244e204 InstallationDate: Installed on 2015-01-01 (139 days ago) InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2) IwConfig: eth0 no wireless extensions. lo no wireless extensions. Lsusb: Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 002: ID 80ee:0021 VirtualBox USB Tablet Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub MachineType: innotek GmbH VirtualBox ProcEnviron: TERM=linux PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 VESA VGA ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-53-generic root=UUID=032922f2-3fe1-4228-8c93-8c1e9afc4289 ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.13.0-53-generic N/A linux-backports-modules-3.13.0-53-generic N/A linux-firmware 1.127.12 RfKill: SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 12/01/2006 dmi.bios.vendor: innotek GmbH dmi.bios.version: VirtualBox dmi.board.name: VirtualBox dmi.board.vendor: Oracle Corporation dmi.board.version: 1.2 dmi.chassis.type: 1 dmi.chassis.vendor: Oracle Corporation dmi.modalias: dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:rvnOracleCorporation:rnVirtualBox:rvr1.2:cvnOracleCorporation:ct1:cvr: dmi.product.name: VirtualBox dmi.product.version: 1.2 dmi.sys.vendor: innotek GmbH To manage notifications about this bug go to: https://bugs.launchpad.net/nmap/+bug/1457472/+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
