[ruby-core:92472] [Ruby trunk Bug#15779] After NoMemoryError, ruby freezes and takes 100% CPU

[buzz.taiki@gmail.com]

Issue #15779 has been updated by buzztaiki (Taiki Sugawara).


I test this reproduction code at ruby 2.5.5 (ruby 2.5.5p157 (2019-03-15 revision 67260) [x86_64-linux]). In this version, this issue is not reproduced (ruby is not frozen).


```
~/opt/ruby/2.5.5/bin/ruby a.rb
#<StringIO:0x0000560b317f53b8 @base_uri=#<URI::HTTPS https://www.ruby-lang.org/>, @meta={"server"=>"Cowboy", "strict-transport-security"=>"max-age=31536000", "content-type"=>"text/html", "etag"=>"W/\"91e880089832f50e7e7bf1371600cc60\"", "x-frame-options"=>"SAMEORIGIN", "via"=>"1.1 vegur, 1.1 varnish", "content-length"=>"424", "accept-ranges"=>"bytes", "date"=>"Mon, 29 Apr 2019 01:11:21 GMT", "age"=>"1800", "connection"=>"keep-alive", "x-served-by"=>"cache-hnd18749-HND", "x-cache"=>"HIT", "x-cache-hits"=>"1", "x-timer"=>"S1556500281.267699,VS0,VE6", "vary"=>"Accept-Encoding"}, @metas={"server"=>["Cowboy"], "strict-transport-security"=>["max-age=31536000"], "content-type"=>["text/html"], "etag"=>["W/\"91e880089832f50e7e7bf1371600cc60\""], "x-frame-options"=>["SAMEORIGIN"], "via"=>["1.1 vegur", "1.1 varnish"], "content-length"=>["424"], "accept-ranges"=>["bytes"], "date"=>["Mon, 29 Apr 2019 01:11:21 GMT"], "age"=>["1800"], "connection"=>["keep-alive"], "x-served-by"=>["cache-hnd18749-HN
 D"], "x-cache"=>["HIT"], "x-cache-hits"=>["1"], "x-timer"=>["S1556500281.267699,VS0,VE6"], "vary"=>["Accept-Encoding"]}, @status=["200", "OK"]>
Traceback (most recent call last):
a.rb: failed to allocate memory (NoMemoryError)
```


----------------------------------------
Bug #15779: After NoMemoryError, ruby freezes and takes 100% CPU
https://bugs.ruby-lang.org/issues/15779#change-77820

* Author: buzztaiki (Taiki Sugawara)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.6.2p47 (2019-03-13 revision 67232) [x86_64-linux]
* Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
Run following reproduce code, ruby freezes and takes 100% CPU.

```
require 'open-uri'

begin
  "a" * 10000000000
ensure
  p open('https://www.ruby-lang.org/')
end
```

But interestingly, the following code does not reproduce this issue.

```
require 'open-uri'

begin
  begin
    "a" * 10000000000
  rescue NoMemoryError
    raise
  end
ensure
  p open('https://www.ruby-lang.org/')
end
```

It was also reproduced when put `sleep 100` in ensure clause, run it and hit Ctrl-C. But `puts 'XXX'` does not reproduce it.


---Files--------------------------------
strace.txt (377 KB)


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