Bug #11404: Segfault when 'throw' occurs while loading a Ruby source file [PATCH]

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.3.0dev (2015-07-23 trunk 51355) [x86_64-linux]
• Backport: 2.0.0: REQUIRED, 2.1: REQUIRED, 2.2: DONE

[alexdowad (Alex Dowad)]

Dear Ruby people,

Here is a fix for a segfault which can occur when requiring a Ruby source file inside a Timeout.timeout {} block. This may seem like a strange thing
to do, but it can easily happen unintentionally if you use libraries which 'autoload' their source files (like RSpec, Rails, etc).

I have observed this segfault in MRI 2.1.2 and 2.3.0.

Thanks,
Alex Dowad

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset r51439.

---

load.c: avoid segfault when 'throw' occurs in the middle of rb_load_file_str

How can a 'throw' happen while the current thread is reading a Ruby source file
from disk and parsing it? It can happen if another thread calls Thread#raise,
and passes an Exception object which responds to #exception, and the custom #exception
method calls Kernel#throw.

In practice, this is most likely to happen if you combine the use of autoload and
Timeout.timeout.

An extra check is required to avoid a segfault in this case.

• load.c (rb_load_internal0): extra check before returning TAG_RAISE when a
  non-local transfer of control happens while loading and parsing a Ruby source file.
  [ruby-core:70169] [Bug #11404]

[nobu (Nobuyoshi Nakada)]

• Backport changed from 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN to 2.0.0: REQUIRED, 2.1: REQUIRED, 2.2: REQUIRED

[nagachika (Tomoyuki Chikanaga)]

• Related to Bug #11481: Segmentation fault when thread is killed during `require`. added

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.0.0: REQUIRED, 2.1: REQUIRED, 2.2: REQUIRED to 2.0.0: REQUIRED, 2.1: REQUIRED, 2.2: DONE

r51292, r51439 and r51440 were backported into ruby_2_2 branch at r52655.
r51292 seems required to r51440 works well.

[nagachika (Tomoyuki Chikanaga)]

Backport r51445 into ruby_2_2 branch at r52661 to suppress warning in CI.