Comment 1 for bug 1654137

I am also seeing this problem. In case it was not clear from Paul's original report, it affects guests using a serial console.

Also, it is not specific to NetBSD. I can reproduce it using a Linux guest on a Linux host, by running the following on a Debian 8 system:

  wget http://landley.net/aboriginal/downloads/old/binaries/1.4.5/system-image-i686.tar.gz
  tar xfz system-image-i686.tar.gz
  cd system-image-i686
  sh run-emulator.sh

and typing Control-A b m once the guest has started.

Using qemu 2.1.2, this successfully causes the guest to print a memory usage summary. Using current qemu sources from git (dbe2b65566e76d3c3a0c3358285c0336ac61e757), nothing happens.