Infinite loop in libcppnetlib-uri.so causing 100% CPU usage

[gary_parker]

Here’s the link to the post where blocking port 1900 was mentioned:

100% CPU Usage

I’m also seeing this problem on v1.14.1.5488-cc260c476 running in Docker with host network, and using an OpenWrt router running miniupnpd 2.1.20180706-1. As I’m not willing to disable UPnP on my router, I decided to find a workaround. At first I tried to add a firewall rule on the Docker host to drop packets with destination port 1900. This didn’t help however. After some tcpdumping, I noticed that Plex contacts the UPnP daemon, and receives a reply on a port other than 1900, but with source po…

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@RealDeuce

My Plex box is directly on the internet. It does run minissdpd and miniupnpd, but if Plex is trying to get an IGD to open a port, it will be asking my ISP, not itself.

It’s not trying to open a port, it’s querying the IGD for it’s IP address to check if it’s double-NAT’d. I believe that, even with Remote Access turned off, PMS still queries any IGDs it finds on the LAN and parses their replies (badly).

Also, lots of detail on past packet dumps of PMS’s SSDP and GDM activity here:

After switching to Plex Pass PMS is constantly utilizing one core (version 1.14.1.5488)

@ChuckPa, just did what you asked: Re-enabled UPnP on router. Shutdown Plex Start dumpcap on the box running PMS Start Plex Waited until CPU usage for one core rose to 100%. There are SSDP messages going through the network but they’re not continuously hammering by any means. Instead they come in bursts of 10 or so packets and then pause for a while (a good 20-30 seconds) and then there’s another burst. I even let the capture go on for a while after Plex started pegging the CPU to see if the…

It’d be interesting to see if you’re seeing similar behaviour on your network.