From: buzz.taiki@...
Date: 2019-05-16T17:07:24+00:00
Subject: [ruby-core:92685] [Ruby trunk Bug#15779] After NoMemoryError, ruby freezes and takes 100% CPU

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


Thank you for your reply!
In my environment, this patch with ruby 2.6.3 has been fixed this issue (ruby was not frozen)!!

```
~/opt/ruby/bug15779_v2_6_3_fix/bin/ruby ~/tmp/a.rb
#<StringIO:0x000055914e06fda8 @base_uri=#<URI::HTTPS https://www.ruby-lang.org/>, @meta={"server"=>"Cowboy", "strict-transport-security"=>"max-age=31536000", "content-type"=>"text/html", "etag"=>"W/\"91e88008983
2f50e7e7bf1371600cc60\"", "x-frame-options"=>"SAMEORIGIN", "via"=>"1.1 vegur, 1.1 varnish", "content-length"=>"424", "accept-ranges"=>"bytes", "date"=>"Thu, 16 May 2019 17:04:03 GMT", "age"=>"1082", "connection"=>"keep-alive", "x-served-by"=>"cache-hnd18751-HND", "x-cache"=>"HIT", "x-cache-hits"=>"1", "x-timer"=>"S1558026243.322961,VS0,VE0", "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"=>["Thu, 16 May 2019 17:04:03 GMT"], "age"=>["1082"], "connection"=>["keep-alive"], "x-served-by"=>["cache-hnd18751-HND"], "x-cache"=>["HIT"], "x-cache-hits"=>["1"], "x-timer"=>["S1558026243.322961,VS0,VE0"], "vary"=>["Accept-Encoding"]}, @status=["200", "OK"]>
Traceback (most recent call last):
/home/taiki/tmp/a.rb: failed to allocate memory (NoMemoryError)
```

```
cat ~/tmp/a.rb
require 'open-uri'

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

----------------------------------------
Bug #15779: After NoMemoryError, ruby freezes and takes 100% CPU
https://bugs.ruby-lang.org/issues/15779#change-78045

* 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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