From: kubo@...
Date: 2015-06-28T05:26:51+00:00
Subject: [ruby-core:69760] [Ruby trunk - Bug #11001] 2.2.1 Segmentation fault in reserve_stack() function.

Issue #11001 has been updated by Takehiro Kubo.


> Any criteria where works on or not?
> Runtime kernel versions?

Segmentaion fault
* Ubuntu 12.04 - kernel 3.2+
* Ubuntu 12.10 - kernel 3.5
* Debian 7.7 - kernel 3.2.63
* Debian 7.8 - kernel 3.4.105

No problem
* Ubuntu 13.04 - kernel 3.8
* Ubuntu 14.04 - kernel 3.13 or 3.16 (I deleted the VM. I don't know which is used.)
* Ubuntu 15.04 - kernel 3.19.3
* Debian 8.1 - kernel 3.16.7

Ubuntu
https://en.wikipedia.org/wiki/List_of_Ubuntu_releases#Table_of_versions
Debian 7.7
https://www.phoronix.com/scan.php?page=news_item&px=MTgxODY
Debian 7.8
http://news.softpedia.com/news/Debian-7-8-Arrives-with-Security-Fixes-and-Updated-Linux-Kernel-469629.shtml
Debian 8.1
http://news.softpedia.com/news/Debian-GNU-Linux-8-1-Jessie-Officially-Released-483592.shtml

On Ubuntu 12.04, stack size in emacs shell buffer is 8515 and
ruby gets segmentation fault. So I put 'ulimit -Ss 8192' in .bashrc
for workaround. (stack size in gnome-terminal is 8192.)


----------------------------------------
Bug #11001: 2.2.1 Segmentation fault in reserve_stack() function.
https://bugs.ruby-lang.org/issues/11001#change-53137

* Author: Kiyoka Nishiyama
* Status: Feedback
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-linux]
* Backport: 2.0.0: DONTNEED, 2.1: DONTNEED, 2.2: UNKNOWN
----------------------------------------
SEGV depends on stack limit size with 'ulimit -s <size>' .

This shell script [ulimit_change_test.sh] can reproduce SEGV on my Debian environment.
my Linux environment is Debian/GNU Linux 7.8.
But, I cannot reproduce this SEGV on Amazon Linux environment.

result on Debian 7.8

~~~
 $ /tmp/ulimit_change_test.sh 
8515
/tmp/ulimit_change_test.sh: 3 ���: 20470 Segmentation fault      ./ruby --version
8514
/tmp/ulimit_change_test.sh: 3 ���: 20471 Segmentation fault      ./ruby --version
8513
/tmp/ulimit_change_test.sh: 3 ���: 20472 Segmentation fault      ./ruby --version
8512
ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-linux]
8511
/tmp/ulimit_change_test.sh: 3 ���: 20475 Segmentation fault      ./ruby --version
8510
/tmp/ulimit_change_test.sh: 3 ���: 20476 Segmentation fault      ./ruby --version
8509
/tmp/ulimit_change_test.sh: 3 ���: 20477 Segmentation fault      ./ruby --version
8508
ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-linux]
8507
/tmp/ulimit_change_test.sh: 3 ���: 20480 Segmentation fault      ./ruby --version
8506
/tmp/ulimit_change_test.sh: 3 ���: 20481 Segmentation fault      ./ruby --version
8505
/tmp/ulimit_change_test.sh: 3 ���: 20482 Segmentation fault      ./ruby --version
8504
ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-linux]
8503
/tmp/ulimit_change_test.sh: 3 ���: 20485 Segmentation fault      ./ruby --version
8502
/tmp/ulimit_change_test.sh: 3 ���: 20486 Segmentation fault      ./ruby --version
8501
/tmp/ulimit_change_test.sh: 3 ���: 20487 Segmentation fault      ./ruby --version
8500
ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-linux]
8499
/tmp/ulimit_change_test.sh: 3 ���: 20490 Segmentation fault      ./ruby --version
8498
/tmp/ulimit_change_test.sh: 3 ���: 20491 Segmentation fault      ./ruby --version
8497
/tmp/ulimit_change_test.sh: 3 ���: 20492 Segmentation fault      ./ruby --version
8496
ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-linux]
8495
/tmp/ulimit_change_test.sh: 3 ���: 20495 Segmentation fault      ./ruby --version
8494
/tmp/ulimit_change_test.sh: 3 ���: 20496 Segmentation fault      ./ruby --version
8493
/tmp/ulimit_change_test.sh: 3 ���: 20497 Segmentation fault      ./ruby --version
8492
ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-linux]
8491
/tmp/ulimit_change_test.sh: 3 ���: 20500 Segmentation fault      ./ruby --version
8490
/tmp/ulimit_change_test.sh: 3 ���: 20501 Segmentation fault      ./ruby --version
8489
/tmp/ulimit_change_test.sh: 3 ���: 20502 Segmentation fault      ./ruby --version
 $ 
~~~

This SEGV occurs in `reserve_stack()` function.
I suspect that the `buf[0x100]` size is too small for margin.
I attached patch to fix it.


---Files--------------------------------
0001-Bugfix-patch-of-reserve_stack-function.patch (720 Bytes)
ulimit_change_test.sh (211 Bytes)


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