Hi Eric, Am 07.01.20 um 18:04 schrieb Eric Dumazet: > > On 1/7/20 5:32 AM, RENARD Pierre-Francois wrote: >> Hello all >> >> I am facing an issue related to Raspberry PI 3B+ and onboard ethernet card. >> >> When doing a huge transfer (more than 1GB) in a row, transfer hanges and failed after a few minutes. >> >> >> I have two ways to reproduce this issue >> >> >> using NFS (v3 or v4) >> >> dd if=/dev/zero of=/NFSPATH/file bs=4M count=1000 status=progress >> >> >> we can see that at some point dd hangs and becomes non interrutible (no way to ctrl-c it or kill it) >> >> after afew minutes, dd dies and a bunch of NFS server not responding / NFS server is OK are seens into the journal >> >> >> Using SCP >> >> dd if=/dev/zero of=/tmp/file bs=4M count=1000 >> >> scp /tmp/file user@server:/directory >> >> >> scp hangs after 1GB and after a few minutes scp is failing with message "client_loop: send disconnect: Broken pipe lostconnection" >> >> >> >> >> It appears, this is a known bug relatted to TCP Segmentation Offload & Selective Acknowledge. >> >> disabling this TSO (ethtool -K eth0 tso off & ethtool -K eth0 gso off) solves the issue. >> >> A patch has been created to disable the feature by default by the raspberry team and is by default applied wihtin raspbian. >> >> comment from the patch : >> >> /* TSO seems to be having some issue with Selective Acknowledge (SACK) that >> * results in lost data never being retransmitted. >> * Disable it by default now, but adds a module parameter to enable it for >> * debug purposes (the full cause is not currently understood). >> */ >> >> >> For reference you can find >> >> a link to the issue I created yesterday : https://github.com/raspberrypi/linux/issues/3395 >> >> links to raspberry dev team : https://github.com/raspberrypi/linux/issues/2482 & https://github.com/raspberrypi/linux/issues/2449 >> >> >> >> If you need me to test things, or give you more informations, I ll be pleased to help. >> > > I doubt TSO and SACK have a serious generic bug like that. > > Most likely the TSO implementation on the driver/NIC has a bug . Yes, the issue isn't reproducible with the Raspberry Pi 3B and the same kernel (without +). The main difference between both boards is the different ethernet USB chip: Raspberry Pi 3B: smsc95xx Raspberry Pi 3B+: lan78xx > > Anyway you do not provide a kernel version, I am not sure what you expect from us. It's Linux 5.4.7 (arm64) as in the provided github link. I asked Pierre-Francois to report this issue here, so the issue get addressed properly. Currently this very old bug not fixed in mainline and the Raspberry Pi vendor tree uses a workaround (disable TSO). Stefan
