Date: Fri, 29 Jan 2021 12:54:27 +0000 From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 252913] [tcp] Using RACK leaks mbufs Message-ID: <bug-252913-7501-7TkG636JDb@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-252913-7501@https.bugs.freebsd.org/bugzilla/> References: <bug-252913-7501@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D252913 --- Comment #24 from iron.udjin@gmail.com --- (In reply to Michael Tuexen from comment #23) 1. For such looping TCP connections at Nov 16 2020 I wrote script which che= cks if SENDQ greater 1700000 and drop them use tcpdrop: netstat -p tcp -n | awk '{print $3" "$5" "$6}' | egrep "^[0-9]" | grep -v '= ^0\ ' | while read line; do SENDQ=3D`echo $line | awk '{print $1}'` if [ "$SENDQ" -gt "1700000" ]; then echo $line | awk '{print $2}' | awk -F\. '{print $1"."$2"."$3"."$4" "$5}' | xargs tcpdrop XXX.XXX.XXX.XXX 443 > /dev/null echo -n "`date`: " >> /root/check_drop.log echo "$line - DROPPED" >> /root/check_drop.log fi done # cat /root/check_drop.log | wc -l 460 Sometimes the script kills 5-10 connections/hour. Sometimes nothing in a da= y. I'll disable this script and when I catch such connection, I'll post sysctl net.inet.tcp.rack output. >So could you start without enabling RACK, start capturing traffic with tcp= dump, enable RACK, ensure that some connection hit the bug, and stop the ca= pturing. 2. It's impossible because very low percent of connections hit such looping state. And that's happening not right after enabling RACK. On the picture I wanted to show how looping connections increases traffic volume. I assume t= he connection should hit a few conditions to start looping. I can write script which with a certain frequency will collect network vaia= bles and write output to the log file. Tell me please frequency and variables wh= ich you need to see and I'll share logs via private link by webserver (will ema= il you credentials). --=20 You are receiving this mail because: You are on the CC list for the bug.=
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