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Segfault possibly caused by mysql2 0.4.0 (with test case) #1063

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64kramsystem opened this issue Aug 29, 2019 · 4 comments
Open

Segfault possibly caused by mysql2 0.4.0 (with test case) #1063

64kramsystem opened this issue Aug 29, 2019 · 4 comments
Milestone
0.4.11

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@64kramsystem
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64kramsystem commented Aug 29, 2019 •
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Hello!

I'm getting a segfault under certain circumstances. I'm not sure what is the exact cause, but it may be related to mysql2.

Test setups and issue reproducibility:

  • Ruby 2.4.6, Rails 5.0.7, mysql2 0.5.2 -> ok
  • Ruby 2.4.6, Rails 4.2.11.1, mysql2 0.4.10 -> kaboom!
  • Ruby 2.5.5, Rails 4.2.11.1, mysql2 0.4.10 -> kaboom!
  • Other setups also caused the segfault

My system is an Ubuntu 18.04-based distro. The db is MySQL 8.0.13 (defaults: utf8m4/utf8mb4_0900_ai_ci; note that Rails sets, by default, the charset to utf8).
I've reproduced it on two separate machines (but configured in a very similar way).

Test case, to be run with bash:

MYSQL_USER=
export MYSQL_PWD=
export MYSQL_SOCKET= # fill only if required

ruby -v # 2.4.6
gem install rails --version '~> 4.2.0'
rails new testjor
cd !$
bin/spring binstub --remove --all # rails new --skip-spring has no effect
echo "gem 'mysql2', '~> 0.4.0'" >> Gemfile
bundle install
bundle exec gem list '^(rails|mysql2)$' # 0.4.10/4.2.11.1
echo 'class MyModel < ActiveRecord::Base; end' > app/models/my_model.rb
mysql -u "$MYSQL_USER" -e 'CREATE SCHEMA testissue; CREATE TABLE testissue.my_models (id INT PRIMARY KEY AUTO_INCREMENT, myint INT, mystr VARCHAR(255))'
perl -i -pe 's/db\/development.sqlite3/testissue/' config/database.yml
perl -i -pe 's/(adapter:) sqlite3/$1 mysql2/' !$
[[ "$MYSQL_SOCKET" != "" ]] && perl -i -lpe '/adapter/ && print "  socket: $ENV{MYSQL_SOCKET}"' !$
bundle exec rails r "MyModel.count" # kaboom!

Segfault output:

<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/mysql2_adapter.rb:57: [BUG] Segmentation fault at 0x0000000000000ba9
ruby 2.4.6p354 (2019-04-01 revision 67394) [x86_64-linux]

-- Control frame information -----------------------------------------------
c:0027 p:---- s:0151 e:000150 CFUNC  :each
c:0026 p:0022 s:0146 E:0004c8 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/mysql2_adapter.rb:57 [FINISH]
c:0025 p:---- s:0141 e:000140 CFUNC  :each
c:0024 p:---- s:0138 E:000130 CFUNC  :map
c:0023 p:0014 s:0134 E:0005b8 BLOCK  <gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:4
c:0022 p:0017 s:0130 e:000129 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:3
c:0021 p:0028 s:0124 E:000490 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:4
c:0020 p:0028 s:0118 e:000114 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/schema_cache.rb:43
c:0019 p:0033 s:0110 e:000108 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/attributes.rb:93
c:0018 p:0022 s:0105 e:000104 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/model_schema.rb:260
c:0017 p:0010 s:0101 e:000100 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:232
c:0016 p:0108 s:0096 e:000095 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:258
c:0015 p:0159 s:0080 e:000079 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:227
c:0014 p:0079 s:0072 e:000071 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:133
c:0013 p:0063 s:0065 e:000064 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:48
c:0012 p:0022 s:0059 e:000058 METHOD <gems_path>/activerecord-4.2.11.1/lib/active_record/querying.rb:13
c:0011 p:0012 s:0051 e:000050 EVAL   <gems_path>/railties-4.2.11.1/lib/rails/commands/runner.rb:62 [FINISH]
c:0010 p:---- s:0048 e:000047 CFUNC  :eval
c:0009 p:0285 s:0040 E:001720 TOP    <gems_path>/railties-4.2.11.1/lib/rails/commands/runner.rb:62 [FINISH]
c:0008 p:---- s:0035 e:000034 CFUNC  :require
c:0007 p:0015 s:0030 E:000ec8 METHOD <gems_path>/railties-4.2.11.1/lib/rails/commands/commands_tasks.rb:123
c:0006 p:0010 s:0025 E:0002f0 METHOD <gems_path>/railties-4.2.11.1/lib/rails/commands/commands_tasks.rb:90
c:0005 p:0036 s:0021 E:000438 METHOD <gems_path>/railties-4.2.11.1/lib/rails/commands/commands_tasks.rb:39
c:0004 p:0123 s:0016 E:001320 TOP    <gems_path>/railties-4.2.11.1/lib/rails/commands.rb:17 [FINISH]
c:0003 p:---- s:0011 e:000010 CFUNC  :require
c:0002 p:0037 s:0006 E:000600 EVAL   bin/rails:4 [FINISH]
c:0001 p:0000 s:0003 E:001d70 (none) [FINISH]

-- Ruby level backtrace information ----------------------------------------
bin/rails:4:in `<main>'
bin/rails:4:in `require'
<gems_path>/railties-4.2.11.1/lib/rails/commands.rb:17:in `<top (required)>'
<gems_path>/railties-4.2.11.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
<gems_path>/railties-4.2.11.1/lib/rails/commands/commands_tasks.rb:90:in `runner'
<gems_path>/railties-4.2.11.1/lib/rails/commands/commands_tasks.rb:123:in `require_command!'
<gems_path>/railties-4.2.11.1/lib/rails/commands/commands_tasks.rb:123:in `require'
<gems_path>/railties-4.2.11.1/lib/rails/commands/runner.rb:62:in `<top (required)>'
<gems_path>/railties-4.2.11.1/lib/rails/commands/runner.rb:62:in `eval'
<gems_path>/railties-4.2.11.1/lib/rails/commands/runner.rb:62:in `<top (required)>'
<gems_path>/activerecord-4.2.11.1/lib/active_record/querying.rb:13:in `count'
<gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:48:in `count'
<gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:133:in `calculate'
<gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:227:in `perform_calculation'
<gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:258:in `execute_simple_calculation'
<gems_path>/activerecord-4.2.11.1/lib/active_record/relation/calculations.rb:232:in `aggregate_column'
<gems_path>/activerecord-4.2.11.1/lib/active_record/model_schema.rb:260:in `column_names'
<gems_path>/activerecord-4.2.11.1/lib/active_record/attributes.rb:93:in `columns'
<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/schema_cache.rb:43:in `columns'
<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:471:in `columns'
<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:324:in `execute_and_free'
<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:472:in `block in columns'
<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:472:in `map'
<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:472:in `each'
<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/mysql2_adapter.rb:57:in `each_hash'
<gems_path>/activerecord-4.2.11.1/lib/active_record/connection_adapters/mysql2_adapter.rb:57:in `each'

-- Machine register context ------------------------------------------------
 RIP: 0x00007f4377f83f20 RBP: 0x0000000000000ba9 RSP: 0x00007fffc3818e28
 RAX: 0x0000000000000000 RBX: 0x0000563ebd500a18 RCX: 0x00007f437161a580
 RDX: 0x00007f43782e1310 RDI: 0x0000000000000ba9 RSI: 0x0000000000000ba9
  R8: 0x00007f437832d010  R9: 0x0000563eba9885a0 R10: 0x0000000000000030
 R11: 0x00007f4377e73540 R12: 0x0000000000000ba9 R13: 0xffffffffffffffff
 R14: 0x0000563eba98f770 R15: 0x0000000000000000 EFL: 0x0000000000010206

-- C level backtrace information -------------------------------------------
<ruby_path>/lib/libruby.so.2.4(rb_vm_bugreport+0x769) [0x7f43780075c9]
<ruby_path>/lib/libruby.so.2.4(rb_bug_context+0xd4) [0x7f4377e86a94]
<ruby_path>/lib/libruby.so.2.4(sigsegv+0x3e) [0x7f4377f7b1ae]
[0x7f4377a31f20]
[0x7f4377f83f20]
<ruby_path>/lib/libruby.so.2.4(st_lookup+0x2c) [0x7f4377f8478c]
<ruby_path>/lib/libruby.so.2.4(rb_enc_find_index+0x3b) [0x7f4377e7357b]
[0x7f4371414a21]
[0x7f4371413a0f]
<ruby_path>/lib/libruby.so.2.4(vm_call_cfunc+0xde) [0x7f4377fea83e]
<ruby_path>/lib/libruby.so.2.4(vm_call_method+0xd3) [0x7f4377ffac43]
<ruby_path>/lib/libruby.so.2.4(vm_exec_core+0x5d8) [0x7f4377ff28f8]
<ruby_path>/lib/libruby.so.2.4(vm_exec+0x7c) [0x7f4377ff8f0c]
<ruby_path>/lib/libruby.so.2.4(rb_call0+0xb8) [0x7f4377ffe2f8]
<ruby_path>/lib/libruby.so.2.4(rb_iterate0+0xb6) [0x7f4377fece56]
<ruby_path>/lib/libruby.so.2.4(rb_block_call+0x3c) [0x7f4377fed00c]
<ruby_path>/lib/libruby.so.2.4(vm_call0_body.constprop.152+0x290) [0x7f4377ffdc30]
<ruby_path>/lib/libruby.so.2.4(rb_call0+0xb8) [0x7f4377ffe2f8]
<ruby_path>/lib/libruby.so.2.4(rb_iterate0+0xb6) [0x7f4377fece56]
<ruby_path>/lib/libruby.so.2.4(rb_lambda_call+0x59) [0x7f4377fed0c9]
<ruby_path>/lib/libruby.so.2.4(enum_collect+0x45) [0x7f4377e78a75]
<ruby_path>/lib/libruby.so.2.4(vm_call_cfunc+0xde) [0x7f4377fea83e]
<ruby_path>/lib/libruby.so.2.4(vm_call_method+0xd3) [0x7f4377ffac43]
<ruby_path>/lib/libruby.so.2.4(vm_exec_core+0x5d8) [0x7f4377ff28f8]
<ruby_path>/lib/libruby.so.2.4(vm_exec+0x7c) [0x7f4377ff8f0c]
<ruby_path>/lib/libruby.so.2.4(eval_string_with_cref+0x1d1) [0x7f4377ffcd31]
<ruby_path>/lib/libruby.so.2.4(rb_f_eval+0xde) [0x7f4377ffd29e]
<ruby_path>/lib/libruby.so.2.4(vm_call_cfunc+0xde) [0x7f4377fea83e]
<ruby_path>/lib/libruby.so.2.4(vm_call_method+0xd3) [0x7f4377ffac43]
<ruby_path>/lib/libruby.so.2.4(vm_exec_core+0x449) [0x7f4377ff2769]
<ruby_path>/lib/libruby.so.2.4(vm_exec+0x7c) [0x7f4377ff8f0c]
<ruby_path>/lib/libruby.so.2.4(rb_load_internal0+0xab) [0x7f4377ed21ab]
<ruby_path>/lib/libruby.so.2.4(rb_require_internal+0x848) [0x7f4377ed4948]
<ruby_path>/lib/libruby.so.2.4(rb_require_safe+0x9) [0x7f4377ed4a49]
<ruby_path>/lib/libruby.so.2.4(vm_call_cfunc+0xde) [0x7f4377fea83e]
<ruby_path>/lib/libruby.so.2.4(vm_call_method+0xd3) [0x7f4377ffac43]
<ruby_path>/lib/libruby.so.2.4(vm_exec_core+0x449) [0x7f4377ff2769]
<ruby_path>/lib/libruby.so.2.4(vm_exec+0x7c) [0x7f4377ff8f0c]
<ruby_path>/lib/libruby.so.2.4(rb_load_internal0+0xab) [0x7f4377ed21ab]
<ruby_path>/lib/libruby.so.2.4(rb_require_internal+0x848) [0x7f4377ed4948]
<ruby_path>/lib/libruby.so.2.4(rb_require_safe+0x9) [0x7f4377ed4a49]
<ruby_path>/lib/libruby.so.2.4(vm_call_cfunc+0xde) [0x7f4377fea83e]
<ruby_path>/lib/libruby.so.2.4(vm_call_method+0xd3) [0x7f4377ffac43]
<ruby_path>/lib/libruby.so.2.4(vm_exec_core+0x449) [0x7f4377ff2769]
<ruby_path>/lib/libruby.so.2.4(vm_exec+0x7c) [0x7f4377ff8f0c]
<ruby_path>/lib/libruby.so.2.4(ruby_exec_internal+0xad) [0x7f4377e8cc2d]
<ruby_path>/lib/libruby.so.2.4(ruby_exec_node+0x1d) [0x7f4377e8eacd]
<ruby_path>/lib/libruby.so.2.4(ruby_run_node+0x1e) [0x7f4377e9183e]
<ruby_path>/bin/ruby(main+0x4b) [0x563eb9f4f8eb] main.c:36

-- Other runtime information -----------------------------------------------

[...]
@sodabrew
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Yes, this is correct. There's no release of mysql2 0.4.x that supports the new MySQL 8 encodings.

Is the bug report is that a version of mysql2 older than the current release causes crashes, but the current release does not?

... there's been a few people asking for a new release of the 0.4.x branch. Gaaaah agh, time and effort, etc.

@sodabrew sodabrew added this to the 0.4.11 milestone Aug 29, 2019
@64kramsystem
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Is the bug report is that a version of mysql2 older than the current release causes crashes, but the current release does not?

If I understand correctly, yes: mysql2 v0.5.2 (at least when paired with Rails 5.0.7) does not cause the segfault.

@64kramsystem 64kramsystem mentioned this issue Aug 29, 2019
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@krisleech
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Firstly, thanks for the great work maintaining the mysql2 gem.

I ran in to this today after upgrading Ubuntu. The README seems to suggest that mysql2 version 0.4 works with MySQL 8.x.

The solution for me was simple:

-gem 'mysql2', '< 0.5' # [1]
+gem 'mysql2', '~>0.5.0' # [1]

(I have mysql2 pinned because ActiveRecord needs a specific version)

  • Ubuntu 19.10
  • MySQL 8.0.17
  • mysql2 0.4.x segfaults
  • mysql2 0.5.x works
  • Rails 5.2.3

@krisleech
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Setting the collation might be of help to those using Rails and MySQL 8.

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@sodabrew @krisleech @64kramsystem