From: "Eregon (Benoit Daloze) via ruby-core" <ruby-core@...>
Date: 2023-09-14T14:44:53+00:00
Subject: [ruby-core:114757] [Ruby master Bug#9115] Logger traps all exceptions; breaks Timeout

Issue #9115 has been updated by Eregon (Benoit Daloze).


mame (Yusuke Endoh) wrote in #note-11:
> As a better-than-nothing mitigation, it is proposed to enclose the entire `Logger::LogDevice#write` in `Thread.handle_interrupt(:never) { ... }`.
> It could be a problem if the method takes a very long time because `Timeout.timeout` cannot interrupt the execution, but such a case will be rare (hopefully).

This sounds problematic, especially since that is doing IO, possibly even network IO (e.g. NFS, or logging over some API).

I believe all libraries should only catch specific errors they want to rescue and if that's hard to determine than StandardError at most, never Exception.
Rescuing Exception without re-raise is always a bug (e.g. NoMemoryError/SystemStackError can be silent and that can cause pretty serious inconsistencies and indirectly what looks like memory corruption).


----------------------------------------
Bug #9115: Logger traps all exceptions; breaks Timeout
https://bugs.ruby-lang.org/issues/9115#change-104594

* Author: cphoenix (Chris Phoenix)
* Status: Assigned
* Priority: Normal
* Assignee: sonots (Naotoshi Seo)
* ruby -v: ruby 2.0.0p247 (2013-06-27) [i386-mingw32]
----------------------------------------
Line 577-579 of logger.rb

      rescue Exception => ignored
        warn("log writing failed. #{ignored}")
      end

Thus, when the system times out in the middle of writing a log message, it warns "log writing failed. execution expired" and just keeps right on running.

This is true in 1.9.3 as well. I haven't looked at older versions.

Pardon me while I go grep "rescue Exception" in the entire Ruby codebase, and see whether I can reliably use Timeout at all...

OK, you might check out C:\Ruby200\lib\ruby\gems\2.0.0\gems\activerecord-3.2.13\lib\active_record\railties\databases.rake

All the other "rescue Exception" seem to re-raise it, except maybe C:\Ruby200\lib\ruby\2.0.0\xmlrpc\server.rb and C:\Ruby200\lib\ruby\gems\2.0.0\gems\activesupport-3.2.13\lib\active_support\callbacks.rb





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