Bug #12614
closedSegmentation Fault on Ruby 2.3.1
Description
Description¶
We have an extensive test matrix that tests many versions of Rails over many versions of Ruby. We notice frequent segfaults when running our Rails 3.1 suite with Ruby 2.3.1p112. We run the same suite with Ruby 1.8 - Ruby 2.2 without issues. It appears that our test suite is exposing a subtle bug in Ruby that I suspect that it is related to garbage collection. The segfault does not occur everytime the test suite runs, but if I run the suite in a bash for loop for 100 iterations I usually see 5-10 segfaults. If I turn off garbage collection during the test cases the segfault does not occur over 100 iterations of the test suite.
To Reproduce¶
I tried, but was unable to come up with a minimal reproduction case. Our code and test suite are publically available and I'll list the steps you can follow to reproduce the issue with some additional setup.
- Clone the newrelic rpm github repo from: https://github.com/newrelic/rpm
- git checkout 3.16.0.318
- bundle install
- run the test suite a single time (you probably won't see a segfault): bundle exec rake test:multiverse[rails,env=6]
- run the test suite in a bash for loop for 100 iterations: for i in `seq 1 100`; do bundle exec rake test:multiverse[rails,env=6]; done
Segfault Output¶
Possibly Related:¶
Files
Updated by nobu (Nobuyoshi Nakada) almost 8 years ago
- Description updated (diff)
Updated by nagachika (Tomoyuki Chikanaga) over 7 years ago
- Backport changed from 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN to 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: REQUIRED
Updated by wanabe (_ wanabe) over 7 years ago
- File small_test_newrelic_rpm.patch small_test_newrelic_rpm.patch added
- File segv_without_newrelic.rb segv_without_newrelic.rb added
Reproduced with trunk ruby 2.4.0dev (2016-08-14 trunk 55893) [x86_64-linux]
.
I guess it is related to method table and its extending logic.
hash_table_extend(tbl)
can make LIST_P(tbl->capa) == TRUE
when there are many collision and deleted items.
In the case, tbl->used
is large but tbl->num
is not.
I attach 2 files.
- A patch to newrelic_rpm to shrink test code
- Test code without newrelic
- I'm sorry that I don't know what magic numbers mean.
Updated by nobu (Nobuyoshi Nakada) over 7 years ago
- Status changed from Open to Closed
Applied in changeset r55896.
id_table.c: extend, don't shrink
- id_table.c (hash_table_extend): should not shrink the table than
the previous capacity. [ruby-core:76534] [Bug #12614]
Updated by nagachika (Tomoyuki Chikanaga) over 7 years ago
- Backport changed from 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: REQUIRED to 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: DONE
ruby_2_3 r56019 merged revision(s) 55896.
Updated by wanabe (_ wanabe) over 7 years ago
- Related to Bug #12917: Segfault in list_ids_bsearch added
Updated by wanabe (_ wanabe) over 7 years ago
- Related to deleted (Bug #12917: Segfault in list_ids_bsearch)
Updated by wanabe (_ wanabe) over 7 years ago
- Has duplicate Bug #12917: Segfault in list_ids_bsearch added