Gnus fetch freezes emacs

[Prashant Tak]

Gnus has been freezing sporadically when `gnus-group-get-new-news` is run.
And it keeps on going for hours, I have to manually intercept and signal
`keyboard-quit` and then perform the fetch operation again. This happens
in a very unpredictable manner, so it's hard to replicate. I did manage
to get a profiler report when that happened.

        7367  99% - command-execute
        7367  99%  - call-interactively
        7070  95%   - funcall-interactively
        7070  95%    - gnus-group-get-new-news
        7063  95%     - gnus-get-unread-articles
        7063  95%      - gnus-read-active-for-groups
        7063  95%       - gnus-finish-retrieve-group-infos
        7063  95%        - nntp-finish-retrieve-group-infos
        7063  95%         - nntp-with-open-group-function
        6851  92%          - #<compiled -0x1643a6a03cf748e>
        6416  86%           - nntp-accept-response
        6068  82%            - nntp-accept-process-output
        5873  79%             - nnheader-accept-process-output
          19   0%              + accept-process-output
          34   0%               nntp-find-connection-buffer
           7   0%       gnus-parent-read-child-newsrc
         297   4%   - byte-code
         297   4%    + read-extended-command
          15   0% + ...

The main culprit seems to be `nnheader-accept-process-output` but I
don't know how to proceed further. Appreciate any help/input into the matter.

-- 
Prashant Tak