Backport #7159

SIGSEGV when calling Random#rand after forking

Added by Kristóf Marussy over 1 year ago. Updated over 1 year ago.

[ruby-core:47976]
Status:Closed
Priority:Normal
Assignee:Usaku NAKAMURA

Description

When Kernel#fork is called,
Ruby uninitializes the default random generator Random::DEFAULT
by setting the next field of the struct MT that provides its state to 0.

Kernel#rand correctly initializes this random generator by a seed
when it detects this.
However, Random#rand does not do this and therefore attempting to
call Random#rand in a newly forked child process results in a
segmentation fault, because a null pointer is being dereferenced.

This irb session illustrates the problem:
https://gist.github.com/3888930


Related issues

Duplicates Backport93 - Backport #5661: Segfault in Random.rand with Spork gem Closed 11/23/2011

History

#1 Updated by Nobuyoshi Nakada over 1 year ago

  • Tracker changed from Bug to Backport
  • Project changed from ruby-trunk to Backport93
  • Status changed from Open to Assigned
  • Assignee set to Usaku NAKAMURA

#2 Updated by Usaku NAKAMURA over 1 year ago

  • Status changed from Assigned to Closed

This issue was solved with changeset r37208.
Andrew, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.


merge revision(s) 34977: [Backport #5661]

* random.c (random_s_rand): ensure default PRNG is re-initialized
  after fork.  patched by Eric Wong.  [Bug #5661]

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