Created attachment 840462 [details]
gdb backtrace of claws-mail

In claws-mails (3.17.6 from Tumbleweed) RSS reader RSSyl some messages cause
"endless loops".
The problem happens in Tumbleweed and Leap 15.2 (in Leap 15.2 observed with
claws-mail 3.17.5 from GA and also with 3.17.6 from the update - repo).
But it is not identical, a message which triggers the endless loop in
Tumbleweed can be viewed without problem in Leap 15.2.
Luckily it is only a small percentage of messages which cause this, but if it
happens claws-mail needs to be killed. Viewing the same message after the
restart will trigger the problem again.

In backtraces taken while in this endless loop state I always observed harfbuzz
or pango related entries last on the stack. So maybe the actual problem is in
this area.

Attached several stack traces from claws-mail looping over the same message.
38 is the related message which caused this in Tumbleweed snapshot 20200807
which can be opened in Leap 15.2 with up to date fixes.

I did not observe something similar with Leap 15.1.