Bug #14571: File descriptor leak in resolv.rb

• Status: Closed
• Priority: Normal
• Assignee: -
• Target version: -
• Backport: 2.3: DONE, 2.4: DONE, 2.5: DONE

[quixoten (Devin Christensen)]

There's an edge case in resolv.rb that can lead to file descriptor leaks on a highly saturated system (logstash in our case).

(the cliff at the end is from a restart of the application)

We're using the logstash-filter-dns plugin which uses timeout.

When a timeout fires while waiting for a random port, the new object is never returned to the caller. Instead requester is set to nil. There's no handle to any sockets that were created in the initializer, so they can't be closed, and one ore more file descriptors is leaked.

(This if my first patch submission, let me know what I can fix or do better.)

[nobu (Nobuyoshi Nakada)]

Just to clarify, do those file descriptors get closed by GC?

[nobu (Nobuyoshi Nakada)]

• Backport changed from 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN to 2.2: REQUIRED, 2.3: REQUIRED, 2.4: REQUIRED

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset trunk|r62671.

---

resolv.rb: close socket

• lib/resolv.rb (UnconnectedUDP#lazy_initialize): store new
  sockets before binding, so the sockets get closed when the
  requester is closing.

• lib/resolv.rb (ConnectedUDP#lazy_initialize): ditto.

• lib/resolv.rb (UnconnectedUDP#close): synchronize to get rid of
  race condition.

• lib/resolv.rb (ConnectedUDP#close): ditto.

[ruby-core:85901] [Bug #14571]

From: quixoten (Devin Christensen) [e-mail]

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.2: REQUIRED, 2.3: REQUIRED, 2.4: REQUIRED to 2.2: REQUIRED, 2.3: REQUIRED, 2.4: DONE

ruby_2_4 r62915 merged revision(s) 62671.

[usa (Usaku NAKAMURA)]

• Backport changed from 2.2: REQUIRED, 2.3: REQUIRED, 2.4: DONE to 2.2: REQUIRED, 2.3: DONE, 2.4: DONE

ruby_2_3 r62949 merged revision(s) 62671.

[naruse (Yui NARUSE)]

• Backport changed from 2.2: REQUIRED, 2.3: DONE, 2.4: DONE to 2.3: DONE, 2.4: DONE, 2.5: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.3: DONE, 2.4: DONE, 2.5: REQUIRED to 2.3: DONE, 2.4: DONE, 2.5: DONE

ruby_2_5 r66748 merged revision(s) 62671.