Dear Maintainer,

When I close all iceweasel windows and tabs, two iceweasel processes stay
running, consuming about 99% or 100% CPU (as listed in htop), until I kill them
sending a SIGTERM signal (no need to send a SIGKILL).

Thinking that it might be a plugin problem, I have run iceweasel with the
--safe-mode switch, and the behavior is the same.

I'm also experiencing symptoms very similar to what's described here,
but with a few differences.

I usually run two iceweasel profiles in parallel, profile "A" is a
"normal usage" profile (the one given in the package information below),
profile B is a "media usage" profile (used with -no-remote & -profile).

Very often, seemingly at random after some time of usage or inactivity,
profile A will start using 100% CPU, and when closing this iceweasel
instance the behaviour stays unchanged until a SIGTERM is sent to the
process, which causes the process to exit. Profile B remains unaffected during
this.

I have never observed this behaviour with profile B, and it doesn't seem
to be an interaction issue since it occurs even when only profile A is running.

I'm currently suspecting it might be a specific site element or
something which triggers it (since profiles A & B are not particularly
different, but are commonly used for different sites), but I've yet
been unable to narrow it down at all

src:iceweasel has been superseded by src:firefox-esr in version
45.0esr-1 in March 2016. Transitional packages to ease upgrades were
provided in the wheezy, jessie, stretch and buster releases. The
transitional packages have been removed finally before the bullseye
release in August 2021.
After regular security support for buster ended in August 2022 and LTS
support ended in June 2024, I'm closing the remaining bug reports now.

Andreas